FPtEE MESSMATES. 31 



entrance door, wlilch they keep half open, all the little 

 animals which are sufficiently bold to pass by. The 

 cruelty of these beings knows no bounds. To instal 

 themselves conveniently, they pierce the body of their 

 host, skilfully open his stomach, and live there as 

 Sybarites ; their lodging is in future assured to them, 

 and their fate is bound up with that of their host. Dr. 

 Herklots, who has unfortunately been recently lost to 

 science, communicated in 18G9, to the Academy of the 

 Netherlands, a very interesting memoir on two crusta- 

 ceans of a new species, the Epichtys giganteiis, v^hich lives 

 on a fish of the Indian Archipelago, and the Ichthyoxenus 

 JelUnghausii, which lodges in a fresh-water fish of the 

 Island of Java. It is to the latter that we refer here, 

 and it seems that in this species we are approaching 

 the limits at which commensalism commences. 



The Cymothoes constitute another category of very 

 interesting Isopods; they lodge with their female in the 

 cavity of a fish's mouth. Dr. Blecker, who has so suc- 

 cessfully explored the Indian seas, obtained more than 

 twenty species of these; but unfortunately he has not 

 made a note of the fishes which harbour them. He has, 

 however, made one exception with regard to a fish from 

 the roadstead of Pondicherry, which is two feet long, and 

 is called a Bat. It is known to naturalists under the 

 name of Stromatea Nigra; its flesh is much esteemed, 

 and it carried in its mouth a Cymothoe called by Dr. 

 Bleeker Cymothoe StromateL A cymothoe has also 

 been observed in the mouth of an Indian Chetodon. 

 De Kay found one in a Rhombus in the United States, 

 and De Saussure saw another at Cuba; and lately, 

 Mons. Lafont discovered one in the Bay of Ai'cachon, on 



