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provided with an exopod, reach to the end of the eyes; their nearly straight dactyh are half 

 as long as the propodi. Just as in the female described by Miss Rathbun, one observes a pair 

 of strong spines between the bases of the legs of the 2°'^ pair. The spine between the bases 

 of the 4''^ pair is distinctly larger than that between those of the 5''^ The branches of the 

 petasma are not yet united with one another in these two young specimens. 

 General distribution: Molokai Island (Rathbun). 



31. Pcnaeopsis Challengeri n. nom. 



Syn.: Pcnaeus serratns C. Spenc'e Bate, Report Challenger Macrura, 1S88, p. 268, PI. XXXVII, 

 Fig. I. (nee: Pcnaeopsis serratns A. Mihie-Edvvards). 



Stat. 253. December 10. 5°48'.2 S., 132° 13' E. Near Kei-islands. 304 m. Grey clay, hard and 

 crumbly. i young female. 



In their important paper on the Penaeidae and Stenopidae collected by the "Blake", 

 published at Cambridge, U. S. A., in 1909, A. Milne-Edwards and Bouvier have described as 

 a new variety antillensis of Pcnaeopsis serratns A. M.-Edw. a form, distinguished from the 

 typical species by the arcuate shape of the rostrum and by the existence of a median spine on 

 the sternum between the bases both of the 4'*^ and of the 5"^ pairs of legs. They are, however, 

 inclined to consider this form as the young state of the american Pcnaeopsis serratns A. M.-Edw., 

 which is described in detail in the same paper. The specimen now which was taken at Stat. 253 

 and which is only 43 or 44 mm. long, fully accords with that variety antillensis as regards 

 the armature of the sternum with two spines situated behind one another and therefore 

 it is considered by me to be the young form of that species which (1. c.) was described by 

 Spence Bate also under the name of Pen. serratns. This species, however, that was captured 

 by the "Challenger" at the Fiji Islands and in Torres Strait, seems to be different from the 

 Pcnaeopsis serratns that occurs in the Atlantic and therefore the name of Pen. Challengeri is 

 here proposed for it. Not only, indeed, does the thoracic sternum, both in the male and in the 

 female, show a different appearance in the two species according to the figures that have been 

 published, but the rostrum is apparently also different. In the american Pen. serratns A. M.-Edw. 

 the rostrum usually runs straight forward or sometimes it is directed obliquely upward (vide : 

 Memoirs Mus. Comp. Zoology at Harvard College, XXVII, N° 3, 1909, p. 222, PI. IV, Fig. i), 

 but in the indopacific Pen. Challengeri it is distinctly arched in the adult species (Spence 

 Bate, 1. c. Fig. i) and, both in the adult, typical, american species and in the variety atitillcnsis^ 

 two rostral teeth are always situated on the carapace, while in the indopacific form all the 

 teeth are situated on the rostrum proper. 



In the specimen from Stat. 253 the rostrum that is distinctly arched with the acute 

 tip curved downward, appears as long as the eye-peduncles, not yet reaching to the end 

 of the basal antennular article; it is armed above with 8 teeth that are all situated on the 

 rostrum itself; the 1^' tooth which is a little smaller than the 2°'^, occurs immediately before 

 the orbital margin. The 2"'' — 5"^ teeth are of the same size, the following become progressively 

 smaller; they extend to near the tip, and the foremost tooth is just as long as the tip. Epigastric 



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