204 Bulletin Vanderbilt Marine Museum, Vol. VI 



Order: EUPHAUSIACEA 

 Family: EUPHAUSIIDAE 



Genus: EUPHAUSIA Dana 

 Euphausia alvae, new species 



Plates 56 and 57 



Type: The type series consists of 32 males and 49 females 

 taken by the "Alva" in 140 fathoms (500 meters of wire out) , near 

 Larantuka Village, Flores Island, Flores Straits, October 22, 1931. 



Technical description : This is an Euphausia of the E. simi- 

 lis, crassirostris, tenera group, having but one lateral denticle. 

 This is placed about midway the length of the carapace. The ros- 

 trum of the present species is much as in crassirostris. It begins 

 as a definite laminate carina just anterior to the cervical groove 

 and is dorsally convex on the proximal portion, thence narrowed 

 and concave on the distal two-thirds ; the rostral blade beyond the 

 carapace is directed obliquely upward and extends as far as mid- 

 way the cornea. The rostrum tapers to an acuminate tip and for 

 the distal third of the length is purely laminate, the proximal 

 two-thirds has the inferior rostral margin continuous with the 

 orbital margin, thus forming an expanded triangle proximally, if 

 viewed dorsally ; below this lateral expansion the rostrum on the 

 proximal inferior margin is expanded, ventrally convex for a short 

 distance. The cervical and hepatic sutures are deep and there is 

 also dorsally a deep sulcus on either side of the rostrum, curving 

 obliquely back to the main cervical groove and separating the 

 rostral and orbital areas. The orbital region is dorsally convex 

 and distally hood-like, with the frontal margin convex, slightly 

 projecting, but not extending any further than the eyestalk joint. 

 The hepatic branch is deep and coalesces with the deeper, outer 

 branch of the cervical groove, which delimits the orbit on the lower 

 side and extends to the inferior lateral margin. Below this in the 

 median lateral area there is a sinuate, or double crescentic sulcus, 

 as depicted. (Plate 57). The anterolateral angle is an acute tooth. 

 The postlateral margin of the carapace is transversely excavate 

 in the median region and broadly rounded on both sides. The 

 third and fourth abdominal segments each terminate posteriorly 

 in the median dorsal line in a small triangulate tooth, that of the 

 third segment being the longer, extending upon the fourth seg- 

 ment for nearly one-eighth of its length, while the spine of the 



