434 CRUSTACEA [November, 



2. S. JiUformis^, Body very much elongated, linear; 

 segments distant emarginate each side; antenna, exteri- 

 ores subclavate; tail cuneiform at tip. 



Inhabits Egg-harbour. 



Cabinet of the Academy. 



JBody appearing of only seven segments exclusive of 

 the ultimate one, of equal breadth throughout, sometimes 

 covered with very short filaments; segments emarginate, 

 each side, and separated by wide insisures; ultimate seg- 

 ment nearly as long as the four preceding ones, contrac- 

 ted in the middle of the margin, and suddenly attenuated 

 near the tip into an obtusely cuneiform termination; head 

 elevated on the disk into a tubercle which is sometimes 

 double; eyes hemispherical, very prominent; antenna ro- 

 bust, intermediate ones very short, exterior ones more 

 than half as long as the body, terminal joint perceptibly 

 somewhat thicker than the preceding. 



Length two fifths of an inch. 



Found in company with the preceding species, and 

 may be readily known by its linear form. 



Genus IDOTEA. Leach. 



Body oval, caudal sQgmtnts two or three, ultimate one 

 largest, destitute of lateral appendices, furnished beneath 

 with two laminae, which are elongated, parallel, attach- 

 ed by their external margins and opening like valves; 

 antenna subequal, short. 



SPECIES. 



1. I. coeca^. Body ovate, attenuated behind to an 

 jacute point; antenna equal, approximated at base, without 



