NOTES ON AMPHITBETUS. 



99 



between thein, in that, there exist a certain difference in the appearance 

 of their innermost muscular layer. It can be made out on the cut edge 

 that the original edge of the former adheres to the inside of that of the 

 latter. 



A short distance from the external siphon-opening is found the 

 W-shaped funnel-organ (" Trichterorgan ") with wrinkled surface. 

 (See /. o., Woodcut 2). It is of much the same shape as we know that 

 organ in Alloposus pacificus and in certain species of Octopus. The two 

 lateral ends of the organ are separated from each other by a space of 5 

 mm. on the ventral siphon wall. A valve is not present in the siphon ; 

 nor is there a trace of connective cartilages at the base. The depressores 

 infundibuli (d. i), disposed in the usual way, is thin and membranous. 



The visceral sac is enveloped in a thin, transparent, visceral mem- 

 brane, which is in many parts supplied with chromatophores. The 

 same holds good also for Alloposus pacificus. The development of 

 chromatophores in these parts evidently stands in relation with the 

 transparency of the animal. 



The visceral sac stands in connection with the ventral mantle by a 

 ventro-median septum (v. m. s.). This is sagittally quite short and 

 antero-posteriorly about 10 mm. long. Its anterior edge lies only about 

 4 mm. behind the erstwhile free edge of the mantle. The lateral bands 

 (I. b.\ on either side of the visceral sac, are thin and narrow. Near 

 their outer end is distinctly visible the ganglion stellatum. 



Shortly in front of the visceral insertion of the ventro-median 

 septum and slightly to the left of the median line is situated the anus 

 on the end of a prominence and provided with a pair of small papilla-like 

 processes (an.). The rectum can be traced for a considerable distance 

 along the ventro-median septum on the left side. 



On the right of the septum is seen a blackish patch, which is causéd 

 by the presence of the ink-bag (i.b.). 



Behind this region and symmetrically situated on both sides are a 

 pair of small papillär prominences, on which the oviduct (ovd.) opens 

 externally. (In Woodcut 2, the two openings of the oviducts have been 



