REMARKABLE MARINE SLUG. 311 



family, in having the vent and the gills, which are extruded 

 from it, situated beneath the edge of the mantle, which 

 latter is extended beyond the circumference of the foot, 

 while in all the other genera, as far as I am aware of, 

 the vent and gills are situated on the mantle itself. This 

 genus may be called Hypobranchaa, and will be figured 

 in the * Zoology of the Samarang/ now in course of pub- 

 lication. The species (H. fmca, Adams,) resembles in 

 appearance a large, flat, sandy-coloured Slug, and crawls 

 along in a slow and languid manner over the sandy sur- 

 face. Owing to its exact resemblance in colour and 

 appearance to the floor on which it lives, it is well calcu- 

 lated to escape the notice of many of its enemies. My 

 specimen was mutilated by a spade in the hands of a 

 seaman, owing to this circumstance, and although a con- 

 siderable portion of the foot and mantle was removed, 

 such was the tenacity of the life of the animal that it 

 crawled away apparently as if uninjured. 



Two of the most remarkable Crustaceans to be met 

 with in this Group, are the Scopimera globosa of De Haan, 

 and the Mycteris deflemfrons, of the same naturalist. 

 The Scopimera globosa forms burrows in the muddy 

 banks and sandflats, just above low-water mark, per- 

 forating the surface in every direction. In some parts of 

 Koo-kien-san, these Crabs are so numerous that they 

 impart a peculiar colour to the shores when seen at a 

 little distance. They walk but slowly, and are very in- 

 active in their habits. When disturbed, they make 

 awkward efforts to get out of sight, by quickly burying 

 themselves in the sandy mud like some Macrophthalmi. 



IftiQMycterisdeflcxifrons, although somewhat resembling 



