September 2nd, and satisfactorily identified by the intelligent lighthouse-keeper there, Mr. Agnew.*

The ten Norfolk Bluethroats were all immature, as were the two which occurred in September, 1867, and September, 1881. Seven of them had a pretty fair blue chest-band; and under that a rufous band, with a well-developed throat-spot of a white colour, leading off into rufous. These seven clearly belong to the Arctic or Redspotted Erithacus suecica. They all, Mr. Power informs me, with the exception of one, which was too much shot to be sure about, proved to be males. The remaining three proved to be females, with white throat-spots, without any rufous, except that in one the spot was distinctly tinged buff. At first sight these three might be supposed to be the White-spotted Bluethroat (E. cyaneculus); but taking into consideration the companionship in which they were found, and the remarks of Mr. Seebohm in his 'British Birds,' I have no doubt they are really Arctic Bluethroats (E. suecica) also.†

Mr. Seebohm's experience, after a full examination of a very large series, is, that immature females are always indistinguishable, and even adult females sometimes (1. c. part i. p. 269). His remarks on the subject will repay reading, but are too long to quote here.

Mr. Power has liberally presented one of his Bluethroats to the Norwich Museum, another to Mr. Stevenson, and two to me. One I received in the flesh, and, after I had skinned it, submitted the gizzard to Mr. F. Norgate for minute examination. Mr. Norgate found its contents to be forceps of two earwigs, a cocoon of a small moth (probably one of the Tineina), two small univalve shells, two skins of larvæ, and the elytra and other hard parts of many small beetles. I took the following measurements while in the

*Mr. Agnew tells me, on August 31st the wind was W. light; on September 1st, in the forenoon, W. light, in the afternoon, S. E. light; on the 2nd, E.S.E. gale and haze. His bird probably crossed the sea before the wind changed to the east.

And likewise the example shot by Mr. Power's brother-Mr. G. E. Power -in 1881, though it was recorded as E. cyaneculus (l. c. p. 350).

There is nothing unlikely in the White-spotted Bluethroat (E. cyaneculus) occurring in Norfolk some day. It is the commoner species in Holland, and I saw a well-marked specimen in Heligoland-where it occurs sometimeswhen there last June, at the shop of Aeüchens the birdstuffer; but at present it seems exceedingly doubtful if it has occurred anywhere in Great Britain, allowing due weight to Mr. Seebohm's observations.

flesh:-Length 5.8 in., tarsus 1 in., expanse 8.5 in.* As I happened to be in Yarmouth when Dr. Babington's bird was killed, I was enabled, through the kindness of Mr. Lowne, to take its measurements also, and, as it was perfectly fresh, the colour of the soft parts-Eye, dark brown; mouth, pale orange-yellow; legs, pale brown; toes, rather lighter. Length, 6 in.; tarsus, 1 in. In two of Mr. Power's males the tarsus measured as much as 1.2 in. It has been said that E. suecica always has a longer tarsus than E. cyaneculus.

IV.

ON NORFOLK AMBER.

BY CLEMENT REID, F.G.S.

Read 29th January, 1884.

DURING a stay of several years on the Norfolk coast, my attention was drawn to the Amber thrown up by the waves, usually after easterly winds. But the many difficulties of Norfolk Geology, and the numerous other problems to be attacked, prevented my making more than a passing allusion to the subject in the Memoir on the Geology of Cromer. Last summer, however, two holiday visits to the coast enabled me to collect further information; and these notes are now brought together, principally in the hope that they may lead other workers to continue the observations.

Amber is found on the Norfolk coast, usually mixed with the sea-weed thrown up by the Spring gales. Mr. Savin has also obtained a small quantity from the Cromer Forest bed at one or two spots, but I can learn of no other instance in which the Amber was found in place. The only resin-yielding trees in the Forest. bed are the Scotch and Spruce Firs, and perhaps the Silver Fir and *This bird was a male.

VOL. III.

S S

Pinus montana.*

Of these the resin is found, very little altered. True Amber is the product of a different Conifer,—the extinct Pinites succinifer, Goepp.,-which we have no reason to believe survived to so late a period as the Newer Pliocene. The absence of this tree, and also the occurrence of large quantities of rolled jet associated with the Amber, lead one to think that in the Cromer Forest-bed, they are both merely present as worn fragments washed out of an older and underlying deposit.+

After long searching unsuccessfully for other evidence of the geological age of the Norfolk Amber, a specimen placed in my hands a few months ago seems to indicate that the Amber-bearing bed is probably the same as-perhaps even nearly continuous withthe well-known deposit on the Prussian coast. Though three or four pounds weight of Amber are annually gathered near Cromer, included insects are extremely rare. Continued inquiry has only resulted in the tracing of four specimens, two of which cannot now be found. The third was picked up on the beach about a year ago by Mr. William Mayes, of Church Street, Cromer, in whose possession it still is. It is a clear wine-coloured piece, containing well-preserved specimens of the larvæ of Aphis, a cast skin of a Spider, and a Chrysotus, considered by Mr. G. H. Verrall to show characters found in some of the extinct Baltic forms. A fourth specimen, from Yarmouth beach, kindly lent me quite recently by Mr. A. S. Foord, F.G.S., is also transparent and winecoloured, and contains three flies. Two of these Mr. Verrallwho I must thank for his examination of the specimens-refers to the genus Leia, both probably belonging to the same species; the third he refers with doubt to Cecidomyia.

Unfortunately, Loew, who studied the Diptera of the Baltic Amber, appears never to have published his species, all the information he supplies being, that he knows twenty-six distinct species of Amber Leia, and so on with other genera, without giving either names or descriptions.§ Mr. Verrall believes that the descriptions were contained in a manuscript work never published. Under these circumstances, nothing further can be done in the identification of

See Saporta, 'Le Monde des Plantes' (1879), p. 349.

+ See Goeppert and Menge, 'Die Flora des Bernsteins' (4to).

§ Loew, Ueber den Bernstein und die Bernsteinfauna' (Meseritz, 1850).

the Amber insects of Norfolk with those of Prussia, till the latter are properly described.

Though the fossils do not yield sufficient evidence on which to correlate the deposits on opposite sides of the North Sea, yet, taken with the geological structure of Norfolk, they point to the original continuity of the bed from Prussia to within a short distance of the English coast. The known eastward dip of the strata in Norfolk, and the thickness of the London Clay at Yarmouth, ought to bring on Upper Eocene and Oligocene beds within a short distance of the coast. Thus the Amber-bearing deposit may have to be added to the list of formations represented in England, if its occurrence within the three-mile limit of the territorial waters could be proved.

The quality of the Norfolk Amber-if I may judge by what has passed through my own hands-is very good, but apparently there is a larger proportion of dark transparent lumps, and less clouded and light yellow than is found in Prussia. Mr. A. S. Foord has kindly cut and examined a microscopic section of clouded Amber for me, and finds that the opacity is due to minute air-bubbles. The size varies much, most of the pieces being small and broken. Mr. Savin has a mass weighing eleven and a half ounces, and it is said that a piece in the possession of Mr. Barker is much larger. The majority of the collections were made in Suffolk, where Amber is perhaps still more abundant, but the character is the same. Further north Amber is also found on the Lincolnshire and Yorkshire coasts; but, from the difficulty of obtaining authentic specimens, it has been thought advisable to confine these notes to Norfolk.

It is possible that some of the worked Amber found in English. tumuli may have been made out of native material; but it seems more probable that it was imported, for the manufacture would only be understood in a district where the raw material was comparatively plentiful. Though the present annual yield is more than sufficient to account for all the ancient Amber ornaments yet found in England,-if we may consider it a fair criterion of the former supply, yet it must be remembered that, were it not for the constant gathering of sea-weed for manure, nearly all the pieces would be overlooked, and destroyed by the waves.

V.

DARKNESS AND EYES

[ABSTRACT].

BY SIDNEY F. HARMER, B. A., B.Sc.

Read 29th January, 1884.

THE visual organs of animals which have lived during many successive generations in total, or nearly total, darkness, exhibit much departure from the normal type. Such animals may be grouped as follows:-(1) Those that inhabit caves. (2) Deep-sea forms. (3) Pelagic animals. (4) Parasites which live within the

bodies of their hosts.

The Cave animals have been especially studied in the United States and in Austria; as, for example, in the Mammoth Cavern in Kentucky, which consists of many miles of perfectly dark galleries, excavated by the action of water on the limestone rock; and in many others in different parts of North America. The Austrian caverns are smaller, and are situated to the north of the Adriatic Sea, near Trieste.

Schiödte has divided the Cave fauna into four groups. The Shade animals, which are found near the mouths of the caverns, and which differ little from those living outside; Twilight animals, inhabiting darker recesses;-these have small eyes, the comparative absence of light having rendered their visual organs of little use ;the Cave animals proper, of which a large proportion are perfectly blind; and, lastly, animals inhabiting the stalactite caverns of Austria, which are all quite blind. These last show remarkable adaptations for climbing over the pillars of stalagmite, in which occupation they spend most of their time.

One of the most interesting animals of the Austrian caves is the blind newt-like Proteus anguinus. It has small eyes, but they are completely covered by the skin, so as to be useless; their structure