the. oilit^ scx tbA second pair of jfeei are monodaciyle^ 

 k>ngcr tliaa the first;, with the lamellary appeiidice oj^ 

 the inner Uase much eiongated, compressed, attenuaf^ 

 ed^ nedifarm^ two-thirds the length of the foot) hody^ 

 eJghthj niuthj and tenth sej^mcnts deatate at ti\eir pos-^, 

 teiior tips above^ v/ith seven strong, prominent teeth<^ 

 of wliich the dorspJ one is shortest ; tail^ two first seg-- 

 Eicnts armed at tip above Vr iih two promhicnt aciitt?. 

 teeth. 



Length three-tenths of an inch. 



This animal corresponds w ith the generic characteri^ 

 in liaving the accessory seta to the antennae^ and the 

 >movea])le spines on the tail^ though it is observable 

 timi these spines are few in number and not fasciculat- 

 iul. But in the form of the four anterior feet it differs 

 very mucli froni the other individuals of this genus, 

 and makes a near approadi to OrcJiestia, from which 

 J.t is difitlnguishedby the length of the superior antennasj 

 (>r v/hlch the characters agi'ce with those of Gammarus. 

 The remarkable elongation of tlie inner lamella of tlic) 

 second psir of feet in one sex is a very striking pecu- 

 liarity of tiiis species^ more especially observable as tlia 

 fzr^i themselves are concealed when at rest;, and that so 

 cFeciiially; that although confident of their existence i(^ 

 was not V, iti5out considerable difficulty that I brought 

 them to vic^v. In consequenee of tliis relative posi- 

 don of the second pair of feet and their appendices, the 

 l,at(er would be mistaken for the feet, by any one who- 

 was not attentive to the general organizalion of these 

 f ai'tfi. It ir' p-cbable that this amra?il wiU ft^rm a i^jiiv 



