1908.] OF SXAKES OF THE GEXUS CORALLUS. 14& 



other. In specimen E the spleen has traces of this peculiar form 

 in that the rounded spleen closely attached to the nearly detached 

 piece of the pancreas is reinforced by a splenculus situated three- 

 quarters of an inch from it, which latter tails off into a thin 

 process. In the other specimens the spleen is a single rounded 

 body as I have described it in Corallus madagascariensis. The 

 pancreas would appear therefore to be pretty constant in its 

 characters in Coi'allus cookii. This form of pancreas seems to 

 be characteristic of the family Boidje among the Ophidia. T find 

 in Eryx conicus a practically identical arrangement ; so also in 

 Python seb(e*. I have already described as chai^acteristic of 

 Eunectes miti'imts f that the pancreas is divided into two portions, 

 of which one is apposed to the duodenal wall and the other is 

 attached to the distantly situated spleen. The duct of the gland 

 connects these two parts. It is possible that in that snake thei-e 

 is also an isthmus of pancreatic tissue lying along the duct ; in 

 any case there is cei^tainly this isthmus in the other sei-pents 

 to whose pancreas I have referred above. In Python sjnlotes 

 much the same structure of these organs is to be seen ; and, 

 m.oreover, in that Python, as in Eunectes micrinus, the spleen is 

 reinforced by additional splenculi, seen also rarely in Corallus 

 cookii. On the other hand, Eoa constrictor differs in that the 

 spleen is close to, but not much in contact with, a solid pancreas 

 unprovided with any discrete fragment and connecting isthmus. 



The organs in Boa constrictor are, in fact, constructed on the 

 plan of those of the non-Boine snakes, where, however, the 

 connection between spleen and pancreas is sometimes rather 

 close. In Vipera russelli the smaller spleen sits like a cap upon 

 the larger pancreas. In Dasypeltis scabra the two " glands " are 

 in absolute contact, and in Helicops angulatus the spleen is 

 actually imbedded in the wider distal end of the pancreas, 

 appearing upon its surface in the form of two patches. Von 

 Siebold and Stannius, in their well-known and usually (so far as 

 my own experience goes) accui'ate and comprehensive text-book of 

 comparative anatomy t, do not sum up acciu-ately the relations 

 of the pancreas and the spleen Avhen they write : " Die Milz ist 

 getrennt vom Panci'eas bei Eryx. Python, Chersydrus, nur wenig 

 ihm anhangend bei Boa. Die Verbindung ist inniger bei den 

 iibrigen Schlangen." These observers would seem to have missed 

 the process of the pancreas so common among the Boidfe. The 

 fact that it is common in that group, and not, as it would appear, 

 found elsewhere, has some significance. For among the Lacer- 

 tilia there is very generally a long and thin process of the 

 pancreas which comes into actual contact with, or at least gets 



* In another example of Pi/tJion sehte tbe distal portion of the pancreas was 

 completely separated from the larger duodenal portion bj' an actual break in the 

 connecting isthmus, bridsed only bv the pancreatic duct. 



t " Contributions to the Anatomy of the Ophidia," P. Z. S. 1906, p. 25. 



J 'Handbucli der Zootomie,' Bd. ii. Amphibia, 1856, p. 187. It is perhaps 

 remarkable that Cuvier and Milne-Edwards have no observations upon these pcinte 

 in their text-books. 



