Boone, Crustacea, Cruise of "Alva," 1931 205 



fourth segment is only one-fourth as long as the spine of the 

 third segment. The sixth abdominal segment is one and a 

 half times as long as the fifth segment and has the postlateral 

 angle a simple blunt triangle. From the median ventral sur- 

 face of the sixth segment there arises a single, strong, curved 

 spine, directed posteriorly, as in E. similis. The telson has 

 the general contour of E. similis G. 0. Sars, but has a definite 

 median longitudinal groove, margined on either side by a coarse 

 carina ; upon these carinae there are situated two pairs of articu- 

 lated spines. The distal margin of the telson is stylet-like, mar- 

 gined on either side by one of a pair of long, stylet-like spines, 

 each of which projects the distal third of its length beyond the 

 apex of the telson. The uropoda are quite like those of E. similis, 

 with a short peduncle and the inner blade a little shorter than the 

 telson, very narrow ; the lateral margins coarsely crenulate, con- 

 verging to a subacute apex. The outer blade is slightly longer 

 than the inner blade, but is also shorter than the telson, and has the 

 inner margin crenulate, the distal margin narrowly rounded. 



One of the most distinctive specific characters of E. alvae is 

 to be found in the antennular peduncle. The first peduncular joint 

 has the distal lobe directed outward and upward and consists of a 

 single, proximally wide, triangulate, acuminate process arising 

 on the inner half of the distal margin and bent somewhat outward 

 and upward, projecting a third of the length of the second article; 

 the outer half of the distal margin is coarsely crenulate, but there 

 is no secondary triangular process, such as is found in E. similis 

 and variety crassirostris. The second peduncular article of E. 

 alvae terminates distally in a strong tooth at the upper distal 

 angle and a similar lesser tooth at the inferior distal angle ; there 

 are two longitudinal light carinae on this joint, the outer one 

 being subparallel to the outer lateral margin, and the inner carina, 

 also extending the length of the joint, is nearly parallel to the 

 outer carina, being only a little closer to it distally than proxi- 

 mally, as depicted. The third peduncular joint is very distinc- 

 tive, in that it has double longitudinal carinae ; the inner one ex- 

 tends nearly the entire length of the article and terminates in an 

 acute subdistal tooth directed forward and upward; the second 

 carina is along the outer part of the upper side of the article and 

 proximally is subparallel to the inner carina, but distally the outer 

 carina curves inward, almost touching the inner carina. Below 



