POETUNUS. 45 



obtaining food in the summer only, at which season the 

 fishermen's nets intercept them and their prey together; 

 and it is probable that in colder weather they keep at the 

 bottom in deep water ; from which however I have never 

 seen them brought in the stomachs of fishes. So far as my 

 observation extends, it is chiefly or only the male that pur- 

 sues this actively predaceous existence ; but that for a time 

 they also remain quietly at the bottom appears from the 

 fact, that while for the most part the smooth and flattened 

 carapace is clean, I have seen it covered with small coral- 

 lines (Sertularue) " 



Gen. 15. POETUNUS, Fair. 



Carapace broader than long; front narrow, projecting. 

 Outer antennae inserted on the same line as the eyes and 

 the inner antennas, their basilar joint united to the front, 

 and completely separating the orbit from the antennary fos- 

 sette. The tarsus of the second, third, and fourth pairs of 

 legs elongated, narrow, pointed, and grooved ; tarsus of the 

 hind legs very wide, oval. Abdomen of male triangular. 



Mr. Gosse found the young of a species of Portumis on 

 the Devonshire coast. They were about one-fifth of an inch 

 in length, and had assumed much of the form of a crab, 



