1118.] OF THE UNITED STATES. 393 



SPKCIES. 



C. abbreviatus^. Hands of the second pair with the 

 laliTi two toothed; branchia oblong oval* 



Inhabits on the Baiaena . 



Cabinet of the Academy. 



Body ovate, narrowed towards each end, anterior feet 

 attenuated towards the base, hand smallest, second pair 

 of feet with the hand much dilated, larger than the oth- 

 ers, palm armed with two large, obtuse, nearly equal 

 teeth, one placed near the base and the other near the 

 tip, thumb as long as the palm; branchia oblong oval, 

 rather more than half as long as the feet, placed upon the 

 breast; anus simple. 



Length less than one tenth of an inch. 



This description is taken from several specimens, 

 which were presented to the Academy by Mr. Reuben 

 Haines^ and which were procured by him from the Ba* 

 laena . 



It appears to differ from the C. Ceti more especially 

 in being much smaller and having the branchia much 

 shorter and more dil-ated. Doctor Leach has substituted 

 for the name of this genus, that of Larunda, in conse- 

 quence of the term Cyamus having been applied by Mn 

 Salisbury to a genus of plants. 



Order V. ISOPODA. Latr. 



^. 



Head distinct from the thorax, simple; eyes sessile, 

 granular; mandibles destitute of palpi; maxilla: three pairs, 

 exterior ones labiform, with two palpi united at base: 

 branchim subcaudal. 



