WEST AMERICAN CRUSTACEA. 577 



second joint has a laminate expansion on the inner side; 

 the third joint equals or somewhat exceeds the last two 

 and has the inner margin concave ; the last joint is about 

 twice the length of the preceding one and armed around 

 the tip with nine to eleven spines. 



The first pereopods are exceedingly short but stouter 

 than the succeeding pairs; the carpus is excavated so as 

 to receive the rounded lobe of the hand; the hand is 

 broadened and thickened at the base where it is produced 

 backwards into a prominent lobe ; fingers excavated, their 

 tips furnished with several small spines. Second pereo- 

 pods slender, much longer than the first pair, but shorter 

 than the third, the carpus three -jointed (the first joint 

 the longest) ; hand slender, not half as long as the carpus, 

 fingers excavated within. The last three pairs of pereo- 

 pods decrease successively in length. 



Abdomen slender, not at all crested or carinated; the 

 postero-lateral angles of all of the segments except the 

 last one rounded. Telson truncated and spinulous at the 

 tip and furnished with a few spinules near the lateral 

 margin. 



Length of specimen, 38 mm. 



Color, green. 



Taken in Bodega Bay, July, 1894. 'The females were 

 loaded with ova. 



Family MIEKSIID^. 

 MiERSIA PACIFICA Sp. nOV. 



Rostrum about as long as the carapax, slender, taper- 

 ing uniformly to the tip; there may be either one or two 

 spines on the upper side and on the under side the num- 

 ber of spines varied in the specimens examined from five 

 to nine. The spines are less distant from each other near 

 the base of the rostrum but there may be two close to- 



