59 



reaches the end of the antennular peduncle, appears at first obliquely ascending, whereas 

 the distal half, beyond the i^' antennular article, is curved upward. In both specimens the 

 toothing-formula is i + lO; the epigastric tooth, much smaller than the following, is situated 

 immediately behind the anterior fourth of the carapace and the following teeth slightly decrease 

 in size towards the tip. The carapace and the abdomen are smooth and shining, the shallow 

 depressions and grooves on the 6"i abdominal somite and on the telson being the only parts 

 that are tomentose. The low and obtuse, post-rostral crest is somewhat flattened immediately 

 behind the epigastric tooth, but fades away before reaching the posterior margin of the carapace. 

 Post-ocular tooth small, but sharp. Post-antennular spine strong, produced backward as a 

 salient ridge, the post-antennular groove therefore well-marked; hepatic spine of the same size 

 as the post-antennular, the other grooves as in Pen. monoccros. 



The i^' — 3"i abdominal somites are rounded above, without any trace of carination ; 

 the 4'!^ — 6"i are carinate, the 5"' and 6"i rather sharply, while the carina of the 4H> takes its 

 origin at the anterior third of this somite. The 5"' somite is little more than half as long as 

 the 6''\ and the 6"^ is barely shorter than the telson. 



Eyes reaching to the middle of the rostrum. 



Antennular peduncle a little shorter than the scaphocerite. The outer (upper) flagellum, 

 that is slightly longer than the other, is but little shorter than the distance between the 

 anterior margin of the carapace and the distal extremity of the antennular peduncle : in the 

 larger specimen this distance measures 12,5 mm., while the outer flagellum is 11,5 mm. long. 

 The antennal flagellum is about 2,5-times as long as the body. 



The external maxillipeds extend to the middle of the terminal joint of the antennal 

 peduncle. 



The three chelate legs are armed each with a slender spine at the base, a much 

 smaller spine occurs also at the far end of the ischium of the 1=' legs; the basal spines are of 

 equal length. The P' pair reaches to the base of the terminal joint of the antennal peduncle, 

 the legs of the },^'^ pair reach to the 3'"'^ joint of the antennular peduncle, those of the 4''' 

 project almost as far forward as the legs of the i^' and the pereiopods of the 5'*^ pair, finally, 

 reach to the middle of the antennal scales and are therefore shorter than in Peti. 

 affinis. In Pen. nionoceros (Fabr.) the lower margin of the ischium of the 5'^ legs carries a 

 subterminal, triangular and subacute lobule (Alcock, I.e. 1906, fig. 7); in Pen. elegans^ however, 

 the lower margin is expanded, slightly arcuate, sharp, though entire, but 

 presenting no lobule. The notch at the proximal end of the merus is bounded anteriorly 

 by a rather short, retrorse tooth, that is not curved inward as in Pett. monoceros or iticisipes^ 

 but directed outward; this tooth also is not sharp, but obliquely truncate posteriorly. 

 Beyond this tooth the edge of the merus appears entire, without a trace of the denticles 

 found in Pen. nionoceros (Fabr.). The 5"' legs carry no exopod. 



The petasma will be best recognized from the figures : it terminates in the larger 

 specimen distally in two small anterior and two large posterior lobes, the latter are obliquely 

 furrowed on their posterior surface. In the younger male the posterior lobes show a somewhat 

 other form, each being cut into two lobules. 



59 



