34 



FIRST CLASS OF THE VERTEBRATED ANIMALS. 



In generjil, the Radius forms the principal bone in the fore-arm of the Mammalia, 

 ■while the Ulna is a slender and small bone, which is frequently consolidated with the 

 radius, and terminates in a point before reaching the wrist. There are only a few 

 genera which possess the power of rotating the wrist freely, so as at one time to pre- 

 sent the palm of the hand downwards (pronation)^ and at another time the palm of 

 the hand upwards (^siipmaiion). This power diminishes in proportion as the fore 

 extremities are used for progression, and for supporting the body in standing. While 

 in these positions, the fore extremity is always in a state of pronation. The radius an^ 

 ulna are flattened in the Cetacea and Seal; and in the Elephant the lower extremity 

 of the ulna is larger than that of the radius, a conformation which is peculiar to that 

 animal. 



The Hand is formed of two rows of bones called the Carpus or Wrist ; 

 of one row called Metacarpus; mid of Fingers, each composed of two or 

 three bones, called Phalanges. 



The forms of the wrist and remote extremities vary with the delicacy of the organs 

 pf touch. It is only in few genera that a Hand, properly so called, is found; but 

 when it exists it is always much less complete, and therefore less useful than that of 

 Man. The mechanism of the human hand is exceedingly curious, and admirably 

 adapted for the various purposes of life. Anaxagoras is said to have maintained that 

 Man owes all his wisdom and supeviority over the other amraals to the use of the 

 hand ; but Galen's view of the matter was rather more philosophical. According to 

 him, Man is not the wisest creature because he has hands; but he had hands given 

 him because he was the wisest creature, for it was not hands that taught him the 

 arts, but Reason. The great superiority of the human hand over that of any other 

 animal, arises from the circumstance that his thumb is of a great size and strength, 

 and can be brought in opposition to the fingers. It thus gives him the power of 

 holding whatever he seizes; and were it not for the thumb, various arts and manu- 

 factures of civilized life would either remain unexecuted, or would require the awk- 

 ward concurrence of both hands. Albinus calls the thumb a second hand. " Manus 

 parva majori adjutrix." The want of the thumb, and the absence of fingers of any 

 great length, compel the Squirrel, Rat, and Opossum, to hold objects in both paws. 

 The Cat and Dog, which are obliged to use their fore-paws for progression, only hold 

 objects by fixing them on the ground. The Solipeda and Ruminantia cannot hold 

 objects at all. On comparmg the hand of the Apes with that of Man, which it most 

 resembles, we cannot fail to remark the smallness of their thumbs in proportion to 

 the length of the fingers. These are slender and very long, while the thumb is 

 weak, small, and short. In the Cercopitheci, the thmnb is concealed under the 

 integuments, and their mode of seizing food and bringing it to the mouth differs but 

 slightly from that employed by the Squirrel. The fore-foot of the Horse is termi- 

 nated by a single bone, called the coffin bone, corresponding in some degree to the 

 third phalanx of the human finger, as the pastern, to which it is united, is analogous to 

 the first phalanx. There are also two short and immoveable bones placed behind and 

 cn each side of the coffin bone, called splint bones. 



If we except the Cetacea, all the Mammalia have the first part of their 

 hinder extremity attached to the spine, and formed into a Pelvis or Basin, 

 which, during youth, is formed of three pairs of Bones, the Ileum, attached 

 to the Spine; the Pubis, which forms the anterior; and the Ischium, 

 forming the hinder part of the Pelvis, 



All these bones are generally more narrow and elongated in the quadrupeds than in 

 Man. In no instance do they form a basin like the human Pelvis ; while frequently 

 the distinction between the large and small Pelvis does not exist, and the cavity often 

 looks obliquely upwards, towards the Spine. One class of Mammalia, possessing 

 abdominal pouches, have two small Marsupial bones placed on the anterior part of the 

 Pubis. These are of a flat and elongated form, and serve to support the abdominal 

 pouch of the female ; yet in some species they are also found in the male. 



At the point of union among the three bones of the Pelvis, is placed 

 the cavity, to which the Thigh-bone or Femur is articulated. To this 

 last bone is attached the Leg, composed of two bones, the Tibia or Shin- 

 bone, and the Fibula. 



The Femur is remarkably short in quadrupeds having a long Metatarsus, as in the 

 Horse, and in common cattle ; and the bone is so enveloped with muscle, that the part 

 usually called the thigh is really the leg. The Fibula, in many quadrupeds, bears a 

 striking analogy to the Ulna of the fore-arm, from its declining in size, and becoming 

 united, by anchylosis, with the Tibia, or else appearing merely in a rudimental form. 



This extremity of the Mammalia terminates in a Foot composed of 

 parts analogous to those of the hand, namely, a Tarsus, Metatarsus, and 

 Toes. 



These bones are altogether wanting in the Whale, Dolphin, ana other Sea Beasts. 

 They have no pelvis, properly so called, as the Ischia are absent; yet we find two 

 small isolated bones which may be compared to the ordinary Pubis. 



The head of the Mammalia is always articulated by two condyles upon 

 their atlas or first vertebra. 



This name of Atlas is assigned to the first vertebra, because it sustains the globe of 

 the head. The second vertebra is called the Dentata, or Axis, because it has a 

 tooth-like process, or axis upon which the first turns. *' 1 challenge any man," says Dr 

 Paley, "to produce in the joints and pivots of the most complicated or the most 

 flexible machine that was ever contrived, a construction more artificial, or more evi- 

 dently artificial, than that which is seen in the vertebrae of the Human neck. Two 

 things were to be done. The head was to have the power of bending forward and 

 backward, as in the act of nodding, stooping, looking upwards or downwards, and at 

 the same time, of turning itself round upon the body to a certain extent, the quadrant, 



we will say, or rather perhaps a hundred and twenty degrees of a circle. For these 

 two purposes, two distinct contrivances are employed : First, the head rests immedi- 

 ately upon the uppermost of the vertebree, and is united to it by a hinffe-ioint, upon 

 which joint the head plays freely forward and backward, as far either way as is neces- 

 sary, or as the ligaments allow, which was the first thing required. But then the 

 rotatory motion is unprovided for. Therefore, secondly, to make the head capable of 

 this, a further mechanism is introduced — not between the head and the uppermost 

 bone of the neck, where the hinge is, but between that bone and the bone next 

 underneath it. It is a mechanism resembling a ienor and mortice. The second, or 

 uppermost bone but one, has what anatomists call a process, viz. a projection some- 

 what similar, in size and shape, to a tooth; which tooth, entering a corresponding 

 hole or socket in the bone above it, forms a pivot, or axle, upon which that upper 

 bone, together with the head which it supports, turns freely in a circle, and as far in 

 the circle as the attached muscles permit the head to turn. Thus are both motions 

 perfect without interfering with each other. When we nod the head, we use the 

 hinge-joint, which lies between the head and the first bone of the neck. When we 

 turn the head round, we use the tenor and mortice, which runs between the first 

 bone of the neck and the second. We may add, that it was on another account also 

 expedient that the motion of the head, backward and forward, should be performed 

 upon the upper surface of the first vertebra; for, if the first vertebra itself had bent 

 forward, it would have brought the spinal marrow, at the very beginning of its course, 

 upon the point of the tooth." 



The Brain of the Mammalia is always composed of two hemispheres, 

 united by a medullary layer called the Callous body (Corpus Calloswni), 

 inclosing two ventricles, and enveloping the four pairs of Tubercles, or 

 eminences called the Striated Bodies {Corpora Striata), the Beds of the 

 Optic Nerves (^Thalami Nervorum Opticoruni) , the Kates, and the Testes. 

 Between the Beds of the Optic Nerve is placed the third ventricle, 

 which communicates with the fourth, situate under the Cerebellum. 

 The crura of the Cerebellum always form, under the Medulla Oblongata, 

 a transverse eminence called the Bridge of Varolius (^Po?is Varolii). 



The Brain in the Monkey tribe is rather flatter in the superior siu-face of its he- 

 mispheres than in Man; but in Quadrupeds it is very considerably flatter. In the 

 Dolphin, and other Sea-Beasts, the Brain has a different shape from that of the other 

 Mammalia, being rounded in every part, while its greatest diameter is across. There 

 are no olfactory nerves in the cetaceous animals, while those of quadrupeds are of an 

 enormous size, especially in the larger herbivorous tribes. 



The proportion which the size of the Brain bears to that of the entire Body, varies 

 greatly for different Mammalia. Even in the same individual it will change with the 

 degree of fatness, or with the age of the animal. As these circumstances cannot be 

 supposed to affect the powers of the mind very materially, we may naturally inquire 

 how the relative size of the brain, and of the entire body, can be assumed as the 

 measure of intelligence in an animal. To enable the student to form his own con- 

 clusions on this subject, we annex the following Table, showing the proportion that 

 the size of the whole body bears to that of the Brain in several animals : — 



The Squirrel Monkey (^Callithrix scivreus), . . as 22 to 1 



Capuchin Monkey (Cebus capucinus), , .. . ... 25 ... 1 



Striated Monkey {Jacchus vulgaris^, . . . ... 28 ... 1 



Field Mouse (^ArvicoJa vulgaris), . , , .... 31 ... 1 



Man, according as he is young or old, . as 22, 25, 30, and 36 ... 1 



The Mole {Talpa Europcea), as 35 ... 1 



Coaita Monkey (^Ateles paniscus) , ...... 41 ... I 



Mouse (^Mus musculus), , . . , .... 43 ... 1 



Varied Monkey ( CercopiMec7i5 mona), , . ... 44... 1 



Gibbon (Hilohates lar), 48 ... 1 



Collared Mangabey Monkey (^Cercopithecus JEthiops), ... 48 ... 1 

 Rat (^Mus decumanus), . . . . . ... 76 ... 1 



Ruffed Lemur (^Lemur Macaco'), . . . .... 84 ... 1 



Porpoise {^Delphimis pkoccena), ...... 93 ... 1 



Great Bat ( Vespertilio Noctula), 96 ... 1 



Dolphin (^DeJpkinits delphis), . as 25, 36, 66, and 102 ... 1 



Great Baboon {Papio Maimoji), ... as 104 ... I 



Barbary Ape {Inmts magotus), . . . .... 105 ... 1 



Vevvet{Mustelafuro'), 138 ... 1 



Rabbit (^Lepus cunicuhis), ... as 140, and 152 ... 1 

 Cat {Ftlis catus), . . . . as 82, 94, and 156 ... 1 



Hedgehog (Erinaceus EuroptEus), . . . .as 168 ... 1 



Fox (^Ca7iis vulpes), ......... 205 ... 1 



Ca\i (Bos taiirus junior), ..... ...219 ... 1 



Hare (Leptis timidus), ........ 228 ... 1 



'WoM (Canis lupus), 230 ... I 



Panther (Felis pardus'), ........ 247 ... 1 



Ass (Equus asimis), . . . , , .... 254 ... 1 



Bear {Uisus arctos), ........ 265 ... 1 



Beaver (Castor Jiher), 290 ... I 



Sheep (Oi'w cj-ies), . , -• . .as 192, and 351 ... 1 

 IVIarten ( Vivcrra martes), . . . . .as 365 ... 1 



Dog (Canis famiUaHs), as 47, 50, 67, 154, 161, and 366 ... 1 



Horse (Equus cahallus), . . , . .as 400 ... 1 



Domestic Hog (Sus scropha), ....... 412 ... 1 



Elephant (Elephas Indicus), . . . . .... 500 ... 1 



Wild Boar (Sus scropha), , . 672 ... 1 



Ox (Bos taurus), . . . ' 860 ... 1 



From the above Table it would appear that the Brain is proportionably largest in 

 the smaller animals. Man is surpassed in this respect only by a small number of 



