64 



the longer flagellum of the male bears, at one-sixth of its length from the base, a small tooth, 

 the acute tip of which is curved backward ; the flagellum is here a little broadened and between 

 the tooth and the peduncle, it is slightly concave ; in the female this tooth is wanting. 



The narrow antennal scales are, in the male, nearly as long as the antennular peduncle, 

 but in the female a little longer than it; the flagellum is, in the male, about one and a half 

 as long as the body. 



The external maxillipeds reach, in the male, to the distal third or fourth of the scales, 

 in the female to near the apex ; they bear an antrorse spine at base. 



Both in the male and in the female the i^' pair of legs are bispinose, the 2°'^ unispinose, 

 the following unarmed; the spine at the base of the 2°*^ legs is smaller than those of the i*' 

 pair. All the pereiopods show a somewhat more slender form than those of Pen. conigei% 

 var. andaniancnsis \ all are provided with an exopod. The legs of the 3'''i pair reach with their 

 chelae beyond the apex of the antennal scales, in the adult female even with one-fourth of the 

 propodus, those of the 4"^ project almost with their dactyli beyond the eyes, those of the 5'^ 

 reach almost to the far end of the 2"<i antennular article. 



The form of the petasma is different from that of Pc7i. coniger. The petasma is at 

 least half as long as the carapace without the rostrum, measured near the dorsal median line 

 and reaches to the base of the 2°"^ legs; it is asymmetrical, the right lobe always distinctly 

 longer but narrower than the left, which distally is truncate; the right lobe is often 

 somewhat turned outward. 



The thelycum has also another form than that of Pen. philippine^isis (Sp. Bate), Pen. 

 coniger (W.-Mas.) and its variety. It consists of a quadrangular, white coloured, plate, is a little 

 broader than long and longitudinally grooved in the middle of its posterior half; anteriorly 

 this plate is truncate or slightly concave, whereas it ends posteriorly in two obtuse or rounded 

 lobes. The slightly concave, lateral margins join the coxae of the 4"^ legs; immediately behind 

 these coxae a salient lamina runs, at either side, from the lateral margins quite near the 

 posterior end of the plate, obliquely backward, abutting near the coxae of the last pair of 

 legs; the transverse, posterior margin of the sternum is thickened and between this margin and 

 the plate there is a deep concavity. One observes a pair of flattened pointed teeth or spines 

 between the bases of the 2"^"^ legs of the female. This species attains perhaps a still larger size. 



724. Penaeopsis Richtersii (Miers). 



Penaeus Richtersii E. J. Miers, Report Voyage of H. M. S. "Alert", 1S84, p. 564, PI. LII, 



Fig. A. 

 Metapenaeiis richtersii M. J. Rathbun, in: U. S. Fish Comrriission Bulletin for 1903, Part III, 



Wash. 1906, p. 904, PI. XX, Fig. 2 and Fig. 57 (in the text). 



Stat. 240. November 22 till December i. Banda-anchorage. From 9 — 45 m. Black sand. Coral. 

 Lithothamnion-bank in 18 — 36 m. i female. 



This specimen, unfortunately bereft of the caudal fan and of the 6''^ and the 5'^^ ab- 

 dominal somites, certainly belongs to this species. The rostrum that reaches to the middle of 

 the eye-peduncles, is armed with 5 teeth besides the epigastric tooth, the 2^^ tooth is situated 



64 



