338 Mr. Clark on the Animals 



Testa ovato-oblonga, tenuisslm^, albidii, nitida, striis trans- 

 versis catenatis iiolata, latere columnari arcuato, apice sub-obluso, 

 vix umbilicato. Long, plusquam \ unc. Lat. -jL unc. 



Ayiimul on the upper part yellowish white, the shield or anterior 

 portion, and the lateral lobes caused by the reflection of the foot 

 on the back, sprinkled with close set, very minute, reddish browa 

 points. The posterior part of the body divided into one or two 

 digitations. Length of the animal when in motion ^^^ths inch ; 

 breadth, ^'gths inch. 



Shell oval-oblong, very thin, white, pellucid, shining, marked 

 with chain-like transverse stria;. Columcllar margin arcuated; 

 apex rather obtuse, scarcely umbilicated. Length, more than |th ; 

 breadth -J^th inch. 



I believe that the animal which contains this very beautiful 

 shell has never before been met with by any Conchologist. The 

 specimens in cabinets are usually procured from fine sand. I had 

 the good fortune to obtain a number of these animals, and some 

 of the next species, alive, at Exmouth and Torquay, from pools at 

 the time of the lowest spring tides ; some of these I preserved in 

 spirits, and others 1 kept alive some hours ia sea water for dis- 

 section and observation. 



The animal is a Lamarckian Bullcea, having the body convex 

 above, divided transversely into two portions, with the margins of 

 the foot reflected upwards on oach side of the back, giving the 

 animal the appearance of being quadrilobated : it has no distinct 

 head, eyes, or tentacula ; the respiratory organs are quite at the 

 posterior extremity covered by the shell, and the admission and 

 expulsion of the water to and from these, by the dilatation and 

 contraction of that part, was very perceptible. The use of the 

 digitations of the hind part of the body, I plainly observed, was 

 for the purpose of assisting the animal in its movements. It is 

 furnished with a strong gizzard composed of three similar angular 

 testaceous plates sharply pointed at each end. The shell of this 

 species, in its catenated striae and general shape, is not unlike the 

 Scaphander catcnaius of Dr. Leach, dredged at Scarborough, which 

 I presume (not having seen the animal) is a Bulla'a ; but this is 

 quite distinct. 



