Dr. E. F. Kelaart on new species of Ceylonese Mollusca, 495 



sionally buries itself in sand, with only the head and tentacles 

 exposed, and lies for hours in this position. 



Order TECTIBRANCHIATA. 



Animal usually provided with a shell both in the larva and 

 adult state. Branchiae covered by the shell or mantle. Sexes 

 united. 



Fam. PleurohrancliidaB. 



Genus Pleurobranchus, Cuv. 



Animal oblong, fleshy, convex above, with a very large and over- 

 spreading mantle. Foot large, equally outspreading, and 

 thus leaving a wide canal all round the body. Head distinct, 

 furnished with a veil, uniting on each side with the borders 

 of the foot, and with two tubular tentacles, which are split 

 anteriorly ; mouth at the extremity of a proboscis. Branchise 

 composed of a double row of lamellae, forming a plume on the 

 posterior right side, between the mantle and the foot. Anus 

 carried by a small tube behind the branchise. Organs of 

 generation in front. Shell sometimes rudimentary, mem- 

 branous, with a tolerably distinct apex hidden in the thick- 

 ness of the mantle. — Woodward. 



Pleurohranchus citrinus ?, Riippell. 



Orange-red. Mantle darker than the other parts of the animal, 

 and speckled with whitish spots. About 1 inch in length. 

 Ova reddish, in circular broad coils. 



Very common in Trincomalee. Found at low-water, on coral 

 stones and sea-weed, nearly throughout the year. Spawns in 

 May, June, and July. 



Pleurohranchus reticulatus ?, Gmel. 



Pale orange-red, reticulated mantle, and spotted with purple. 

 About 3 inches long. 



Found near Fort Frederick, Trincomalee, in shallow water, 

 among rocks. 



Pleurohranchus zeylanicus, Kel. 



Pale yellow, splashed with darker yellow and brown, and mi- 

 nutely spotted with rusty brown. About 2 inches long. 



Rare; found in Back Bay. 



Pleurohranchus purpureus, Kel. 



Deep reddish purple. Mantle very dark purple, and spotted 



