498" HABITS OF MOLLUSKS. 



(Z. Adamsii, White) is of a light pink-colour with dark 

 red-brown longitudinal stripes. It is perfectly smooth, 

 polished, and hairless. Lissocarcinus and Gonatonotus, 

 two other new Genera, besides numerous new species, 

 were likewise obtained along this coast. 



The Chitons, in the tropics, appear to be more vivacious 

 than those found further north. If turned over on their 

 backs they will gradually bend their calcareous jointed 

 bodies in every direction, contracting and dilating their 

 ventral disk until they assume their natural position. 

 Their progressive motion is scarcely perceptible however, 

 the principal object apparently being again to fix them- 

 selves to the surface of the rocks which Nature has given 

 them to inhabit. Their food consists of Fuci and other 

 Algae, with which the rocks and stones are covered, and 

 their excrement is solid, and formed like that of an insect 

 in the larva state. 



Among coral masses on this north-west coast of Borneo, 

 a large and handsomely-marked species of Vermetus was 

 found, the head of which is elongated, flattened, tapering 

 behind, broader in front where it is divided between the 

 tentacles into two lobes; the tentacles are compressed 

 vertically, conical in form, with the small sessile black eyes 

 situated at their outer bases ; the mantle, with a thick- 

 ened rim, forms a wide loose tubular sheath around the 

 sub-cylindrical body ; the foot is circular, but without ex- 

 hibiting any of those tentacular appendages usually ob- 

 served in this genus, the margin being simply thickened ; 

 the operculum is large, circular, flat, and horny, with 

 concentric elements ; and, when the animal is retracted, 



