26 



was not, however, any trace of these fragments of shell in the pyloric or pan- 

 creatic laminated bag. 



The liver {z. z. pi. 4.) is a bulky gland, extending on each side of the crop 

 from the oesophagus to the gizzard. There is a parallelism of form, as will be 

 afterwards seen, between this gland and the respiratory organs ; for instead of 

 being simple and undivided as in Ocythoe, or bilobed as in Sepia, it is here divided 

 into two lobes on each side, and these are connected by a fifth portion which 

 passes transversely below the fundus of the crop. All these larger divisions are 

 subdiAaded into numerous lobules* of an angular form, which vary in size from 

 three to five lines. These lobules ai-e inmiediately invested by a very delicate 

 capsule, and are more loosely surromided by a peritoneal covering common to 

 this gland and the crop. 



The hver is supplied by large branches which are given off" from the aorta, as 

 that artery winds round the bottom of the sac to gain the dorsal aspect of the crop. 

 It is from the arterial blood alone, in tliis, as in other MoUusks, that the secretion 

 of the bile takes place; there being but one system of veins in the liver, which re- 

 turns the blood from that viscus, and conveys it to the vena cava at its termination. 

 The colour of the liver is a dull red with a violet shade ; its texture is pulpy and 

 yielding. Wlien the capsule is removed by the forceps, the surface appears under 

 the lens to be minutely granular or acinous ; and these acini are readily separable 

 by the needle into clusters hanging from branches of the blood-vessels and duct. 

 The branches of the duct arising from the terminal groups of the acini, form, 

 by repeated anastomoses, two main trunks, which unite into one at a distance 

 of about two lines from the laminated or pancreatic ca\-ity {h. fig. 8. pi. 8.). 



Beyond this part no other foreign secretion enters the ahmentary canal, as 

 there is not in the Pearly Nautilus any trace of structure analogous to the ink- 

 bag of the Dibrancliiate Cephalopods. 



§ 4. Circulating and Respiratory Systems. 



The peritoneum, after hning the cavity which contains the crop and liver, and 

 enveloping those viscera, forms two distinct pouches at the bottom of the palhal 

 sac ; in one of which, the left {I. pi. 5.), is contained the gizzard ; in the other 

 (m. pi. 5.), the ovary : anterior to these, and on the ventral aspect of the liver, 



* I have lately met with a similarly subdivided form of liver in Caproynys, a Glirian quadruped from 

 Cuba. 



