110 On the genus Onchidium. [No. 2, 



Explanation of letters in Plates XIV and XV. 



oe. — oesophagus. 

 ac. — alimentary canal. 



ps. — supplementary albuminous gland of the penis. 

 I. — liver. 

 r.— rectum. 

 t. (or ts) testis. 

 o. (or as in fig. 5) ovarium, 

 p. — penis, 

 pp. — penis opening, 

 sg.— salivary glands. 

 pe. — eye-pedicle. 



tt. — tentacle, except in fig. la, of PI. XIV, being = buccal 

 appendage. 

 i. — intestine. 



pst. — first portion of the stomach. 

 st. — middle portion of the stomach. 

 mst. — muscular, middle part of the same. 

 on. — terminal part of the same. 

 ag. — albuminous gland of the generative organs. 

 as. — in fig. 2, albuminous gland of the testis. 

 lit. — heart. 



rs.~ receptaculum seminis. 



gp. and pa. — supplementary glands (kidneys, &c. ?) of the rectum. 

 go. or g v. — hermaphrodite genital opening. 

 a. — (in figs. 2 and 5) anus. 

 ol.— pulmonary orifice. 

 I. — lungs. 



rm. — retractile muscle. 

 n. — nerves. 

 ng. — chief ganglion. 

 dn. — nerve of the digestive organs. 

 hs. — base. 



cp. — cartilaginous plates supporting the radula. 

 to. — tongue. 

 ra. — radula. 



