Invertebrate Gallery of the Indian Museum 73 



are popularly known as Spider-crabs. The Oxyrhynchs 

 are, for the most part, timid and inoffensive crabs trtisting 

 to their spiny integument for protection from their enemies, 

 or else bedecking their carapace with fragments of sponge 

 and coralline etc., for concealment. 



Three families of the Oxyrhyncha are represented in 

 the Gallery : 



ist Family, Inachidge — Tjipical Spider-crabs, several 

 species of which live at considerable depths. 

 To this family belongs the gigantic Macrocheira 

 kxmpferi from Japan, a specimen of which is 

 exhibited beside Case 64. The genera from 

 the Indian shallow seas are Huenia^ Doclea, 

 Egeria, and from the depths the huge Platy- 

 maia, Echinoplax, Encephaloides, Anamathiay 

 Pugettta, Oxypleurodon. 



2nd Family, Waiidse.—The genera O^mn/^, iI//Mr^;f, 

 and Micippa, of which specimens are exhibited 

 in Case 64, are found on the reefs of the 

 Indian Seas. 



3rd Family, Parthenopldse. — The genera Lambrus and 

 Parthenope are common in the Bay of Bengal 

 at depths of 20 to 60 fathoms. Observe the 

 great length of their chelipeds and the wonder- 

 ful sculpturing of their carapace. 

 4th Tribe, Oxystoma, Case 68. — In this tribe the mouth- 

 frame, instead of being square as it is in other crabs, is 

 triangular, and is often produced in front to a point, 

 whence the name Oxystome or " Sharp-mouth " : the incur- 

 rent opening into the branchial cavity instead of beiuo- 

 placed at the base of the great cheliped, as it is in other 

 crabs, is very commonly a channel placed alongside the 

 mouth-frame : the carapace is often globular. 



The Oxystomes are, for the most part, feeble and in- 

 offensive crabs, living half-buried in soft mud and sand at 

 the bottom of the sea : some, however, are bold and active 



