MOLLUSOAN GENUS COCHLITOMA. 261 



In these general features there was no difference between the 

 two varieties or the examples of each. 



Neither intestine nor antes differs from those of var. obesa. 



(2) Circulatory and Respiratory System. 



The pericardium is slightly less than half the size of the 

 kidney. In both cases the ventricle is broader and shorter than 

 in zebra. The pulmonary vein of f x was affected by disease. 

 That of f 2 had its secondary branches more evenly distributed 

 than Zj and z 2 . As in z 2 the pulmonary vein was a considerable 

 distance from the ureter. 



(3) Renal System. 

 The kidney measured : — 



f t 55 + 3 x 13 mm. 



f 2 36 ± 2 x 14 mm. 



Even with this variation the kidney is in general appear- 

 ance broader than that of var. obesa. There is no posterior 

 groove and the posterior appendage tends to lie at right angles 

 to the main axis of the kidney. 



(4) Nervous System. 



The remarks made above (p. 254) about the connective tissue 

 sheath and its general significance are relevant in the case of 

 this variety. 



Cerebral Ganglia. — The general shape resembles those of var. 

 obesa. The position and origin of the main roots are more or 

 less identical though there are differences of detail. The buccal 

 ganglia are fairly closely approximated in f 2 , but widely separated 

 by a distinctly differentiated commissure in f . Each buccal 

 ganglion gives off four antero-lateral and one posterior nerve. 

 As in zebra, there are three large labial and pharyngeal nerves. 

 The innermost supplies the lower lip, the next innervates the 

 sides of the mouth and sends a branch to the anterior tentacle 

 (a branch found in obesa), while the third gives off lateral and 

 superior labial and a mandibular branch. Behind and above 

 there arises a very slender auditory nerve and behind and above 

 this the rhinophorial nerve. 



Between this variety and obesa the most important differences 

 appear to be the greater apparent differentiation of the " lobule 

 de sensibilite " and the fact that there are only seven nerves aside 

 in this variety. 



Pedal Ganglia, etc. — The cerebro-pedal connectives are long 

 and slender. As in var. obesa they enter the pedal ganglia in an 

 antero-dorsal position. There is the same tiered arrangement 

 of the pedal nerves, and in f 2 there are seventeen roots aside and 

 probably the same number in f . 



There was not nearly so much enclosure of adjacent pedal roots 

 in common sheaths as in var. obesa. 



