78 



the viscero-branchial connective a very short distance and then enters the bran- 

 chial heart. It is possible that this nerve arises from the visceral ganglion , not 

 from the branchial , and it is also possible that this nerve , not one from the 

 splanchnic ganglion , supplies the systemic heart. 



The Sense Organs. 



The organs of special sense are the statocysts , the eyes , and the organ 

 which is probably olfactory in function. The last is an area of colummar epithel- 

 ium situated in the concavity at the lower end of the "olfactory crest" and 

 innervated by a nerve from the pedal ganglion. 



The Statocysts. 



The statocysts of the Cephalopoda have been described by Hamlyn-Harris 

 and, although he did not have this species before him , his description of 

 the statocysts of Loligo vulgaris holds true for this species. The statocysts lie 

 in the skull below the visceral , and behind the pedal ganglion. The cavity of 

 each is 2 or 8 mm. in diameter and 8 or more mm. in length. They are side 

 by side and are separated by a thin cartilaginous septum. Twelve papillae project 

 into the statocystic cavity. These are situated as follows , passing backward from 

 the first , near the front end , t(j the last , near the back end of the cavity : 

 The first postero-median papilla. 



„ second „ „ „ behind the preceding. 



„ first median „ above the preceding. 



„ antero-raedian „ 



„ first posterior „ 



„ „ anterior „ j The first anterior, the second median 



„ second median „ ; and the second posterior papillae are 



J, ., posterior „ ) included in the same cross section. 



first external „ ( 



„ second „ 



These papillae are side by side and 

 . the first which is bent upward is poste- 

 ) rior to the second which is erect. 



third posterior „ This begins as a ridge on the thick- 



ened posterior part of the septum, runs 

 outward and backward, and ends in a 

 posterior papilla. 



