3 o8 



(the outer branch 3-times), and the stylamblys, which is 5-times as long as thick, is armed at 

 the inner side of its obtuse extremity with about 20 cincinnuli, while 6 or 7 feathered setae 

 are implanted on the inner margin, the outer being glabrous; the inner border of the protopod, 

 finally, is also fringed with long, feathered setae which are not articulated. In the following 

 pleopods the branches gradually diminish in breadth and the stylamblys in length. 



Prionocrangon W.-Mas. 



The remarkable genus Prionocrangon W.-Mas. includes only three species, of which the 

 first described, Prion. ommatósteres W.-Mas., occurs in the Bay of Bengal off the Ceylon coast 

 and in the Andaman Sea, while a male was obtained by the "Siboga" east of the island of 

 Saleyer and a female in the northern part of the Strait of Makassar. The second species, 

 Prion. Dofleini Balss, is recorded from the Sagami Bay, Japan, while the third, Prion. pectinata 

 Faxon, is found in the West-Indies, off Martinique. 



All the species occur in deep water. Prion. ommatósteres was taken by the "Siboga" 

 at Stat. 88 at a depth of 711 fathoms, the greatest depth at which this genus has been 

 observed; this species, however, was obtained off the Ceylon coast also between 200 and 

 350 fathoms. 



Key to the known species of the genus Prionocrangon W.-Mas. 



a x When the carapace is looked at from above, the rostrum appears 



much shorter than the transformed eyestalks. 



Telson considerably shorter than the uropods, abruptly contracted 



behind the middle. Carapacial carina with 8 teeth pectinata Faxon 



(W. FAXON, in: Buil. Mus. Compar. Zoology. Vol. XXX, N u 3, 1896, p. 157, 

 Plate II, figs. 4—7.) 



a„ When the carapace is looked at from above, the rostrum appears 



almost or just as long as the transformed eyestalks. 



b x Carapacial carina 6 — 8-toothed. 



Rostrum rather short onnuatosteres W.-Mas. 



ó 3 Carapacial carina 10 — 12-toothed. 



Rostrum rather long Dofleini Balss 



(H. BALSS, Ostasiatische Decapoden. II. München 19 14, p. 71, fig. 42.) 



1. Prionocrangon ommatósteres W.-Mas. PI. XXV, Fig. 76 — 76/. 



Prionocrangon ommatósteres J. Wood-Mason, in: Ann. Mag. Nat. Hist. 6 t!l Ser., Vol. 8, Nov. 



1891, p. 362. 

 Prionocrangon ommatósteres A. Alcock & A. R. Anderson, in: Journal Asiatic Soc. Bengal, 



Vol. LXIII, Part II, N" 3, 1894, p. 152. 

 Prionocrangon ommatósteres A. Alcock, A descript. Catal. Indian Deep-Sea Crustacea, Calcutta 



1901, p. 123. 

 Illustrations of the Zoology of the Investigator, Crustacea, PI. IX, fig. 4. 



