1855.] Chusan Shells. 129 



Dr. Cantor's specimens from the contraction of the cooked animals, 

 compressing the very fragile shells. The same circumstance may 

 have occasioned the want of success met with in the search for living 

 examples. 



" On entering a house in Tinghae, where the people had just 

 finished their breakfast, Dr. Cantor observed a number of these 

 shells (broken with but one exception,) on a dish. To an enquiry 

 whence they came, the Chinamen asserted, that they were taken in 

 the canal. Although Dr. C. offered a reward and almost daily 

 dragged the canals, he was never able to procure another specimen. 

 The same dish contained shells of Paludina quadrata, which is a 

 favourite food of the Chinese, and is plentiful in all the canals, even 

 close to the sea ; and as the canals communicate with the sea, the 

 Bullcea might possibly have been found in the locality assigned." 



Paludina quadrata, Benson. 



Testa elongato-conoidea, crassa, epidermide viridi-olivaceo, anfrac- 

 tibus sex planulatis, leviter transverse plicatis, longitudinaliter lira- 

 tis ; liris subquinis, apertura mediocri, intus albido-violacea j umbilico 

 arcto, peritremate nigrescente. 



The slightly prominent longitudinal ridges (which, with the flat- 

 tening of the whorls, contribute to give the shell a singular appear- 

 ance,) vary much in number, and in some specimens are nearly 

 obsolete. The operculum is horny. The shell in its thickness and 

 sculpture indicates an approach to the Melaniance, but the animal 

 having the eyes on an exserted pedicle, differs therein from Melania 

 in which the eye is sessile on the tentaculum. It also differs from 

 the ordinary forms of Paludina, in which the eye-supports seem to 

 occupy a common tube with the tentaculum, and to be truncated at 

 the point of divergence. The ridges of the shell are frequently 

 invested with either a vegetable or a spongeous growth, which gives 

 it an appearance of having variegated bands, which do not properly 

 belong to the epidermis. 



" Extremely common in canals and fresh-water ponds, where it is 

 found in the mud, and adhering to stones, wood, aquatic plants or 

 any firm object which may happen to be immerged. The specimens 

 vary in size ; larger specimens were observed, than the one figured. 



s 2 



