114 



ANIMAL KINGDOM. 



face of the water in still warm evenings in tro- 

 pical seas ; some, as the clio borealis, figured 

 above, abound in the Arctic seas. (See PTE- 

 ROPODA.) 



18. Cephalopoda, free cyclo-gangliated or 

 mulluscous animals, with the feet disposed 

 around the head, respiring by internal branchiae, 

 and with the abdominal cavity enveloped by a 

 muscular mantle open anteriorly. The cepha- 

 lopods are all marine animals capable of swim- 

 ming by means of membranous or muscular 

 expansions, which are never supported by rays. 

 The surface of the body is often naked, some- 

 times covered with a shell, which is generallypo- 

 lythalamous, rarely monothalamous, and always 

 inoperculate. There is often a concealed, loose, 

 dorsal, calcareous or horny shell contained in a 

 shut subcutaneous sac. The mouth is fur- 

 nished with two horny or calcified mandibles, 

 and the rudiments of an internal organized 

 cartilaginous cranium and vertebral column are 

 generally perceptible, together with some de- 

 tached parts of the skeleton of vertebrata. The 

 oesophagus is surrounded by a nervous collar, 

 from which two supra-abdominal nervous co- 

 lumns generally extend along the middle of the 

 back, and sympathetic ganglia are observed in 

 the abdominal cavity as in the inferior mollus- 

 cous classes. These are predaceous animals, 

 and the alimentary canal, though generally 

 furnished with three enlargements, forming a 

 crop, a gizzard, and a spiral or proper chylific 

 stomach, is always very short. There are two 

 pairs of salivary glands; the liver is of great 

 size, and pours its secretion, with that of the 

 pancreatic follicles, into the stomach, as in the 

 inferior classes. There is always a strong mus- 

 cular systemic ventricle, and generally a di- 

 vided auricle placed at the beginning of the 

 branchial arteries. The common form of the 

 chylopoietic organs is seen in those of the 

 loligopsis guttata, (Jig. 44,) where the liver 



(a a a ) 

 pours its se- 

 cretion by 

 ducts (/<), 

 which are 

 surrounded 

 and pene- 

 trated by 

 the pancrea- 

 tic follicles 

 (c c), and 

 which unite 

 into a single 

 canal before 

 they open by 

 a valvular 



aperture into the third or chylific stomach (fg). 

 The crop (c/) ends in the strong muscular giz- 

 zard (f), and from the third stomach (,f g) the 

 short intestine (//) ascends in front of the liver 

 to terminate by a valvular anus at the base of 

 the funnel. The naked species have a glandu- 

 lar sac for secreting a black inky matter, which 

 appears to be wanting in those protected by an 

 external shell, excepting in the argonauta, 

 where the shell is seen in the ovum, and where 

 there is a slight membranous connexion be- 



44. 



tween the animal and its thin delicate calca- 

 reous covering. The sexes are generally sepa- 

 rate, but the lowest foraminiferous cephalo- 

 pods appear to approach to the pteropods in 

 the male and female character of the genital 

 organs. (See CEPHALOPODA.) 



The last or highest DIVISION of the animal 

 kingdom, comprehending the vertebrated or 

 red-blooded animals, or SPIN I-CEREBRATA, con- 

 sists of five distinct classes, characterised chiefly 

 by their generative, their sangniferous, and 

 their tegumentary organs, viz. 



19. Pisces, cold and red-blooded oviparous 

 vertebrated animals, with one auricle and one 

 ventricle to the heart, breathing by permanent 

 branchiae, and with fins for progressive motion. 

 They have a vertebral column and cranium, 

 enclosing a spinal cord, and brain consisting 

 of a medulla oblongata, optic lobes, cerebral 

 hemispheres, olfactory tubercles, and a cere- 

 bellum. The hands and feet are always formed 

 like fins for progressive motion in a watery 

 element. The fins are supported by rays pro- 

 longed from the skeleton, the body is generally 

 covered with scales, the trunk is organized 

 for the lateral motion of the tail, there is 

 no sacrum, and the pelvic arch is unconnected 

 with the vertebral column. The bones are 

 elastic or cartilaginous, and the centres of 

 ossification for the most part remain perma- 

 nently detached. The bodies of the vertebrae 

 terminate in two cup-like cavities, they move 

 on elastic tense intervertebral sacs, and the 

 transverse processes are directed vertically 

 downwards in the coccygeal region of the 

 skeleton to facilitate the lateral motion of the 

 trunk. The muscles, of a white colour, are 

 disposed in oblique strata on the sides of the 

 trunk for the movement of the elastic vertebral 

 column. The mouth, destitute of salivary 

 glands, is generally furnished with numerous 

 unequal, irregular, fangless, osseous teeth, and 

 the wide oesophagus, short like the neck, leads 

 to a capacious stomach, from which the in- 

 testine, shorter than in the higher classes, and 

 nearly equal throughout, proceeds, without 

 ccecal enlargement, to terminate in a cloacal 

 sac on the inferior surface of the trunk. The 

 liver is large, and pours its secretion generally 

 by a single duct into the duodenum, near the 

 pyloric extremity of the stomach and close 

 to the opening of the pancreatic duct, as shown 

 in the annexed figures of these parts in the 

 frog-fish (fig. 45, A} and the cod (fg. 45, E). 

 The oesophagus () of the frog-fish (Jig 45, A) 

 leads to a large globular stomach (c) with a 

 strong muscular cardiac sphincter (l>). The 

 pyloric extremity is also surrounded with 

 strong muscular bands ((/), and beyond its 

 pyloric valve two pancreatic simple glandular 

 follicles (e e) open into the duodenum (g) close 

 to the opening of the ductus communis chole- 

 dochus (./'). In the cod (fig. 45, B) the wide 

 oesophagus () leads to a long and capacious 

 muscular stomach shut below, and immediately 

 beyond the pyloric valve, formed by a circular 

 fold of the mucous coat, open the ducts of 

 numerous straight and simple pancreatic folli- 



