278 A HISTORY OF RECENT CRUSTACEA 
Haplostylus, Kossmann, was established to receive the 
Mediterranean species, Gastrosaccus Normani, Sars, which 
is also found off the coast of Ireland, and a Red Sea species, 
Haptostylus erythicus, Kossmann, the generic distinction 
consisting in the absence of the forward directed lobes on 
the concave hinder rim of the carapace, which are found in 
the species of Gastrosaccus above mentioned, and also in 
the recuction to a rudiment of the inner natatory branch 
of the third pleopods of the male. 
It will be seen from the foregoing notes that fifteen 
genera of this family are represented in the Fauna of Great 
Britain, and it is quite possible, and even probable, that 
extended research may show that others of the genera 
and species occur round the very varied coasts of the 
British Isles, which in their southern parts, especially if 
the Channel Islands are included, are in rather marked 
contrast to the region of the Orkneys and the Shetland 
Isles, among which Norwegian and Arctic forms may 
readily present themselves. It will be understood that, 
although an endeavour has been made to mention all the 
valid, or at least all the commonly accepted, genera of the 
Schizopoda, there are very numerous species belonging to 
those genera of which it has been impossible to take 
notice. 
