ONCHIDIUM. 51 



part of the groove between the mantle and the 

 foot ; foot narrowed ; shell none. 

 On rocks near the sea covered with the tides. 



1. ONCHIDIUM. 



Animal oblong ; mantle completely covering the 

 back, convex, coriaceous, tuberculated ; eyes 

 two, at the end of cylindrical retractile pe- 

 duncles ; tentacles none, or in the form of 

 rounded oral lobes or a buccal veil ; jaws none, 

 tongue denticulated ; orifice of reproductive 

 organs widely separated ; pulmonary cavity be- 

 hind the heart, with the aperture posterior, 

 between mantle and foot. 



11. 1. ONCHIDIUM celticum. Oblong mantle thick, 

 coriaceous, rather shining, covered with short 

 thick rounded tubercles, surrounded with smaller 

 ones ; foot oblong. 



Onchidium celticum. Cuvier (?) ; Couch ; Forbes and Hartley, 

 iv. 3. t. FFF. f. 6. 



Inhab. Cornwall, on rock at West Comb in Sand- 

 level Bay (J. CoucJi). 



The edge of the mantle considerably exceeds the 

 foot; the under side of this edge minutely granulated; 

 foot pale yellowish. 



" Jaws none ; tongue broad, and furnished with 

 upwards of seventy transverse rows of blunt slightly 

 curved teeth, each row containing 108 teeth, and 

 divided by a minute central tooth of a triangular 

 form bearing a single blunt spine. The reproductive 

 organs are in the same individual. The male organ is 



E 2 



