Zoological Society^ 411 



5. Notes on certain Molluscous Animals. By Arthur Adams, 

 Esq., R.N., Assistant Surgeon to H.M.S. Samaranq. 



The following notices refer to the animals that construct the shells 

 of Pyrula, Calpurnus, Radius, Terebellum, Rostellaria, Eulima, Stilifer 

 and some others, which I believe have not before been described, 

 though the shells have long been known. The drawings were made 

 from the living moUusks on the spot. 



The genus Bullina of Risso or Cylindrella of Swainson has an ex- 

 ternal subcylindrical shell covered with a thin reddish-brown epi- 

 dermis. The mantle is enclosed ; the foot elongate, linear, truncated, 

 and with three conical tubercles behind. The cephalic disc is sub- 

 trigonal, broad, rounded in front, and produced behind on each side 

 into a flat tapering process, with the eyes on the outer side of its 

 base. They crawl very slowly, moving by an almost imperceptible 

 series of undulations of the foot. Dredged in fifteen fathoms, be- 

 tween Borneo and Billiton. Mr. Gray informs me that M. Lov^n 

 has recently described the animal of a northern species of this genus 

 under the generic name of Cylichna. 



The animal of Akera, Miiller, Vitrella of Swainson, or the Bulla 

 resiliens, is pale brown, with the foot very much expanded, narrower 

 and rounded in front, broad and truncated behind, and with the sides 

 sometimes bent up. The head-disc is elongated, rather broader, and 

 slightly notched in front, but narrower and linear behind. Eyes 

 none. The shell is perfectly external, and there is a fimbriated edge 

 projecting through the slit in the spire. From Unsang, Borneo. 



This animal agrees with Lov^n's description of the northern spe- 

 cies. Miiller figures the animal of Akera bullata, a northern species 

 of this genus, in the 'Zoologia Danica'j and M. Loven in his re- 

 cent work has observed, that MUUer's species emits through the slit 

 in the back of the whorls a series of elongated slender beards, which 

 are appended to the mantle's edge. 



The mollusk that constructs the shell of Bulla smaragdina would 

 appear to form the type of a new genus. The shell is naked above. 

 The foot moderate, rounded before and behind ; the side-edges re- 

 flexed and covering the sides of the shell. The head-disc is five- 

 sided, rather broader on each side in front, flattish above with two 

 small tubercles in front of the central eyes, and narrower and nicked 

 behind. It is amphibious, though entirely marine, crawling slowly 

 on rocks immediately above the ripple of the sea. The eyes are black 

 and sessile ; the tentacula short and anterior to the eyes. The ani- 

 mal is dark olive- green, with the margin of the foot and mantle of a 

 light colour, and mottled and speckled. Cagiani Islands and Disaster 

 Island near Japan. 



In Calpurnus of De Montfort the mantle adheres to the sides, but 

 does not cover the shell. It is dead-white and covered with round 

 black spots. The foot is large, thin, flat, expanded, and marked like 

 the mantle. The tentacula are tapering with a broad black band 

 near their extremities. The eyes are large and black, and are placed 



JJ9* 



