340 PROCEEDINOS OF THE NATIONAL MUSEUM. vol.39. 



variations, especially in the way of prehensile organs. Unfortunately 

 the specimen was crushed before it had been fully examined, and we 

 do not know whether it possessed maxillipeds or not. 



(Sieholdii, from Carl Theodor Ernst von Siebold, an eminent au- 

 thority on the Crustacea.) 



ERGASILUS LIZ^aE Kroyer. 

 Ergasilus lizae, Kroyer, 1863, p. 232. 



Female. — Body elongate, length twice the width, narrowed con- 

 siderably posteriorly. Head fused with the first thorax segment, the 

 two covered by a broad violin-shaped carapace, the posterior portion 

 of which is longer than the anterior. 



The emargination on either side is long and rather shallow, and the 

 posterior margin is almost squarely truncated. 



Free thorax segments diminishing regularly in size, the last one (fifth 

 segment) very short. Genital segment oval, shorter than the first 

 three free segments but longer than wide ; armed on the ventral surface 

 near the posterior margin with a large number of long and coarse bristles. 



Abdomen three-jointed, each joint wider than long and the last 

 one much shorter than the preceding ones, the three together about 

 the same length as the genital segment. Anal laminae the same length 

 as the joint to which they are attached, as wide as long, and armed 

 ■jvith two setse, the inner of which is much the larger. Egg-sacks 

 usually much shorter than the body and quite stout, but in some 

 specimens they are longer than the entire creature, seven or eight 

 times as long as broad. Eggs in three or four longitudinal rows, about 

 one hundred in each sack. 



First antennae short, only reaching the basal joint of the second pair; 

 six-jointed, the two basal joints elongate, the others much shorter and 

 all armed with heavy bristles. Second antennae half the entire length, 

 slender, four-jointed, the several joints in the proportion of 4 : 8 : 7 : 5. 

 The second joint carries a small knob on the center of the concave 

 margin. Eyes fused on the median line, about one-third the distance 

 from the anterior margin of the carapace; eye pigment bright red. 



First four pairs of swimming legs biramose, rami three-jointed, the 

 joints diminishing in size distally; fifth legs uniramose, flattened, 

 one-jointed, and nearly squarely segmented at the distal end, from 

 whence arises a pair of long setae. 



In his description Kroyer gives these fifth legs as appendages of the 

 genital segment at its anterior end, but they belong of course to the 

 fifth thorax segment, which is very short in all the species of this genus 

 and often thoroughly fused with the genital segment. With the 

 exception of this and a few other minor corrections the preceding 

 account is little more than a free translation of that given by Kroyer. 

 No mention is made of the color of this species. 



