ORGAN'S OF DIGESTION. 377 



is covered by the hepatic lobules in octopus, in others, as 

 loligo, it is free and anterior to the liver ; and in others, 

 as sepia, it lies behind the posterior end of the liver, but 

 in none is it organically connected with that chylopoietic 

 gland. The colour of its inky secretion is found to cor- 

 respond with that of the coloured spots of the skin in 

 the different species, and thus to serve as a more perfect 

 means of concealment. 



The liver is large and conglomerate in the cephalopods 

 as in other molluscous classes, and is generally bilobate 

 or quadrilobate in its exterior form. It is separable into 

 four distinct lobes in the nautilus and the loligopsis (122. 

 D. ff. g.}, and in most others it is more or less bifid at 

 its lower margin (122. C. f. f.) ; and these lobes consist of 

 numerous small aggregated lobules, the component tubuli 

 of which, commonly filled with a reddish brown coloured 

 turbid secretion, are short, wide, simple, and straight, like 

 those composing the hepatic acini of the higher Crustacea. 

 This great chylopoietic gland occupies the anterior and dorsal 

 part of the abdominal cavity, separated by its peritoneal 

 covering from the oesophagus and anterior aorta above, and 

 also by its muscular tunic from the gastric and circulating 

 organs behind arid below. As in other molluscous classes, 

 it is destitute of a venous portal circulation and of a gall- 

 bladder, as in them also it is supplied only by branches from 

 the aorta, and its ducts open directly into the cavity of the 

 stomach, not into the intestine as in the vertebrated classes. 

 Its higher development in the cephalopods however is 

 marked, as in the advanced development of this gland from 

 its primitive blastema in the embryos of higher classes, by its 

 greater separation from the contact of the alimentary cavity, 

 and the consequent elongation of its ducts. The bile is 

 poured into the third or spiral stomach by a single duct 

 formed by the union of two or four ducts which descend 

 from the lower and posterior part of the hepatic lobes ; and 

 the aperture by which the bile is conveyed directly into the 

 cavity of the stomach, is here protected by two prominent 

 valvular folds (122. D. d.), which are continued from the sto- 

 mach along the side of the intestine towards the anus. Nu- 

 merous small glands, sometimes in form of simple cellular 

 follicles ( 1 22. C. g.) and sometimes forming lobules of ramified 



