i8 



the posterior border of the carapace carries a few spinules, while it is only granular in the 

 adult species. This young- female therefore fully agrees with the type, except that the anterior 

 division of the lateral border carries 6 spines instead of 4 or 5. 



The carapace of the adult males is three quarters of a telson-length shorter than the 

 abdomen. 



The carinae of the first five abdominal terga culminate each in an 

 acute antrorse spine. The spine of the i^' tergum is small; in the three adult males it is 

 obliquely directed upward, in the other specimens more straightly forward, like in Fig. T,a of 

 the "Illustrations". The spine of the 2"<J tergum projects horizontally forward and is as long 

 as that of the i^'; the 3''^ spine and the 4"^ are more than twice as long as the 2°"^, 

 the 5"^ is almost as long as the 4*. The two edges of the double carina on the 6* 

 tergum are denticulate, presenting 6 to 8 small teeth; they unite posteriorly to an obtuse tooth, 

 which sometimes is a little larger than those of the edges. The carina on the anterior extremity 

 of the telson is cut into two obtuse teeth, situated behind one another, the anterior a little 

 larger than the other. The i^' somite that carries, like in other species, two equal spines at 

 either end of the anterior border, appears, between these spines and the middorsal line, eroded 

 or coarsely punctate. The four following terga are obliquely grooved on each side, like in 

 Stereom. phospJiorus. The grooves are narrow and deep, and widen somewhat at their inner 

 end; on the 3"^, 4''^ and 5''^ somite their posterior border curves slightly backward at their 

 inner end, while it appears straight in the figure of Stereom. phosphorus., and between this 

 posterior border and that of the terga themselves the surface appears eroded and more or less 

 distinctly furrowed transversely. The anterior margin of each oblique groove is indistinctly 

 carved out in the middle, outside this notch one observes a small acute tooth. The anterior 

 margin of the 2"*^ to 5* terga is also carved out, quite conspicuously, just outside the middle, 

 and between this margin and the oblique groove the surface is slightly tubercular. One observes 

 on the upper surface of the 2"^^ to 5'^^ terga on each side a longitudinal crest, just near and 

 parallel with their also carinate, lateral margin; between both carinae there is a groove, like 

 in Stereotn. phosphorus and trispinosa. The 6* tergum appears a little wider in proportion 

 to its length than in Stereom. phosphorus. On either side of the double carina the tergum is 

 covered with some acute granules and this granulated area is bounded laterally, like in Stereom. 

 phosphorus and trispinosa, by a line that runs parallel with the midline of the body, while the 

 triangular interspace between this line and the somewhat tubercular outer margin of the tergum 

 is smooth. The granules of the granulated area are more prominent than in the two other 

 species. The caudal fan resembles that of Stereom. phosphorus, the outer border of the exopodite 

 being very slightly emarginate at the distal end; the submedian, longitudinal ridges on the 

 telson are finely spinulose. 



The pleura are characterized by the strongly curved, ear-shaped midrib, which is m ore 

 or less distinctly interrupted in the middle, and by the lower part of this midrib 

 being higher and more tuberculiform than in Stereom-. trispinosa. On either side of the ear- 

 shaped midrib the pleura are hairy; they are for the rest smooth, except a few sharp granules 

 behind the tuberculiform lower end of the rib on the 3"^ , 4''> and 5'h pleura. The lower edge 



