Professor Owen among the Perisso-dactyle Ungulates. They are small gregarious animals living in holes in the rocks. One species occurs in South Africa, and is called the "badger;" another is found in Arabia and in Palestine, and is supposed to be the "coney" of Scripture. They are not unlike small Rodents, for the canines are absent, and the incisors of the upper jaw grow from permanent pulps; the molars are seven in number on either side of each jaw, and are very like those of the rhinoceros in form and structure.

VI. UNGULATA. This order of herbivorous Mammals includes three entire old orders-Ruminantia, Solidungula, and Pachydermata; the elephant alone being removed from the Pachydermata, and placed in a separate order. All the members of this group are characterized by the possession of four limbs, which are useless for prehension, and only subserve the purpose of locomotion. The toes are encased by hoofs or "nails," and there are never more than four fullsized toes to each leg. The molars have broad crowns, for the purpose of grinding vegetable food. This order is subdivided into two primary sections.

(A). Perisso-dactyles (repíσoos, odd; and dάктuλos, a toe), or odd-toed ungulates, that have either one or three toes; the horns, if present, are never in pairs; and the dorsolumbar vertebræ are more than nineteen. Perisso-dactyles are divided into

1. Solidungulates.

2. Multungulates.

1. The Solidungulates comprise the horse, ass, zebra, quagga, and onagga; all possess a single toe encased in a broad hoof-hence the name (solida, solid, and ungula, a hoof). The bones of the fore leg of a horse are homologous to the bones of the human arm. They are here placed side by side for the purpose of comparison

D

In the same way the bones of the hind leg of a horse are homologous to the bones of the human leg, and what is termed the stifle-joint of a horse corresponds to the kneejoint of man (the stifle-bone being homologous to the patella), and the hock-joint, containing six bones, viz., astragalus, os calcis, cuboid, and three cuneiform, corresponds to our anklejoint. The femur of the horse has three trochanters; the clavicle is absent, and there is no gall bladder.

2. Multungulates (multa, many, and ungulæ, hoofs) comprise the rhinoceroses and tapirs. Rhinoceroses are very large, heavy animals; the feet have each three toes; they have one, or, it may be, two horns; when two are present they are placed in the median line, one behind the other, the posterior one being much the shorter; the horns possess no bony core. The tapirs have four fingers and three toes, and the nose is prolonged into a small, movable proboscis.

(B.) Artiodactyles (aprios, even; and dάктuλos, a toe), or even-toed ungulates, are sub-divided into two groups—

1. Ruminantia.

2. Omnivora.

1. The Ruminants constitute a most important group of the ungulates, and are characterized by their peculiar dentition, by the structure of the stomach, and by that of the foot. The typical dental formula of a Ruminant is

The incisors and canines of the lower jaw are similar in size and form. In consequence of the absence of these teeth in the upper jaw, the lower incisors are opposed to a hardened pad of gum. The camelidæ, however, form an exception, as they possess six incisors in their upper jaw. Ruminants have a complex stomach, which, as previously mentioned, consists of four cavities. In the adult animal the paunch is the largest of these cavities (in young Ruminants the abomasum is the largest), and serves the purpose of a temporary store-house for the food; it is lined with dense squamous epithelium, and secretes a watery fluid, which has little or no digestive function. In the camel tribe this paunch contains a number of pits, the openings into which are closed by muscular sphincters, and are capable of containing a large quantity of water-hence camels are able to travel far across desert plains in consequence of this beautiful provision of nature. The reticulum (rete, a net) is much smaller, and presents a honeycombed appearance. The small polygonal spaces into which it is divided form the food into small round balls, which are regurgitated into the animal's mouth, and are there re-masticated: this is what is termed rumination. The food, after rumination, passes again down the œsophagus, then along a groove situated on the upper margin of the reticulum into the manyplies. The manyplies has its mucous membrane arranged in parallel plates like the leaves of a book, hence its name. There are about eighty of these leaves in the ox, and forty in the sheep; from this cavity the food passes into the abomasum or rennet, which last is the true digestive stomach, and the homologue of the stomach of man.

The foot of Ruminants is always "cloven," and consists of a pair of symmetrical toes encased in hoofs; in a great

many there is a pair of supplementary toes placed on the back of the foot. Ruminants are sub-divided as follows:

1. Ruminants without horns, e.g., Camels, Alpacas. Llamas, and Musk-deer.

2. Ruminants with horns.

a. Horns persistent.

1. Covered by hairy skin, e.g., Giraffe.

2. Covered by horny case (cavicornia), e.g., Ox, Sheep, Antelope, Goat.

. Horns deciduous (Antlers), e.g., Stags (cervidæ).

Three distinct types of horns are found among the ungulata. 1st. Those that consist entirely of epidermic constituents, and are made up by the aggregation of horny fibres: this form is seen in the rhinoceros. 2nd. Those that consist of a central bony core, which is completely covered with a true horny case or hairy skin (vide antea). 3rd. Those that are formed of true bone, termed antlers, and are shed every year.

2. Omnivora, the last division of the ungulata, comprises the well-known pig, also the peccary and hippopotamus. They possess no third trochanter on the femur, and are all remarkable for the thickness of their integument.

VII. MUTILATA. These form a remarkable order of Mammals, and are all adapted for an aquatic life. The anterior limbs are changed into fins, while the posterior ones are wanting. The tail is horizontal and flat, and there are no external ears. Lacrymal glands are likewise absent. The Mutilata are divided into two groups :

a. Cetacea (carnivorous).

b. Sirenia (herbivorous).

Cetacea are the largest of all living Mammals. They com

prise the whale, dolphin, porpoise, and narwhal; they are fish-like in form and mode of life; they have one or two blow-holes on the top of the head, leading into the nostrils; their teats are inguinal, testes are abdominal, and they have no vesiculæ seminales. Their respiration is very peculiar, and the mechanism by which it is performed extremely interesting. It is thus accomplished: the top of the pharynx is guarded by a strong sphincter muscle, which is closed except when the whale expires, and thus prevents any communication between the cavity of the pharynx and the nostrils. The soft palate is greatly enlarged, so as to form a perfect septum between the mouth and the pharynx, thus enabling the whale to swim about under water with its mouth fully open, yet no water can enter its lungs. the blood requires fresh oxygen, the animal rises towards the surface of the water, shuts its mouth, and commences to expire the impure air; the expired column of air is surrounded with a cylinder of water drawn up with it by friction-hence the mistake that these animals spout water. The Cetacea comprise three families, viz., whale-bone whales, sperm whales, and dolphins.

When

The whale-bone whales (balanidæ) have no teeth (the embryo has teeth, which never cut the gum), but possess instead transverse plates of whale-bone (baleen) attached to the hard palate; the inner edge of these plates is furnished with a close fringe of whale-bone fibres, by means of which the small molluscs on which this giant feeds are filtered from the water. They have a thick layer of fat (blubber) beneath the skin.

The sperm whales (catodontidæ, κатά, down; and ỏdoús, a tooth) are characterized by having a single blow-hole, and by having conical teeth in the lower jaw; there are also a few in the upper, but they never cut the gum. These animals are sought after for the spermaceti which is diffused through the blubber, and contained in special cavities in the