It appears to me very probable that the species which has been described by Alcock (1. c.) 

 as Metap. mogiensis, is another as tliat of Miss Rathbun, because the petasma and especially 

 the thelycum show a different form in both species. The specimens collected by the "Siboga" 

 are unfortunately all young, they are perhaps to be referred to Alcock's Pen. inogiensis. 



The largest specimens are the females collected at Stat. 240, which are nearly 60 mm. 

 long. As regards the shape and the toothing of the rostrum, these specimens closely resemble 

 Miss Rathbun's figure of Pen. niogiensis (l.c, p. 40), but the branchiostegal spine is smaller and 

 more resembles that of Alcock's species (l.c. fig. 15). The rostrum is 8+ i- or 9+ i-toothed, 

 the epigastric tooth situated at the anterior fourth of the carapace; it hardly attains the far end of 

 2°<i antennular article. In a female, long 60 mm., the carapace without the rostrum and measured 

 near the dorsal line, appears to be 11,5 mm. long; the 6* abdominal somite, 7,75 mm. long 

 and 5 mm. broad, resembles that of the japanese Pen. mogiensis-^ the telson is 9 mm. long. 



The external ma.xillipeds reach to the end of the antennal scales, the legs of the 4"^ 

 pair to the end of the antennal peduncles, and those of the 5''^ extend just beyond the eyes. 

 All the thoracic legs bear an exopod. 



The ventral spines between the bases of the feet of the 2"<^ pair are well developed, 

 while in the japanese inogiensis they are rudimentary. The thelycum much agrees with Alcock's 

 fig. 15^, but the anterior of the two laminae between the bases of the feet of the s''' pair 

 bears only one tooth at its outer angles. The divergent median teeth between the legs of the 

 4"* pair show a somewhat other form than in Alcock's figure. 



The 9 specimens from Stat. 3 1 3 are still younger. 



The rostrum of the young male from Stat. 258 is 7 + i-toothed and closely resembles 

 Alcock's fig. 15, the upper margin being slightly arcuate. 



The two males from the Jedan islands are 42 mm. long; of the petasma of the male 

 from Stat. 282, only 25 mm. long, the two branches are still separated. 



When this species might afterwards prove to differ from those described by Miss 

 Rathbun and Alcock under the name of Met. inogiensis, I should propose for it the name of 

 Peti. hilarulus. 



f28. Penaeopsis qtiinquedentatits (de Man). 



Penaeiis sp. J. G. de Man, in: Abhandl. Senckenb. Naturforsch. Gesells. XXV, 1902, p. 906, 



Taf. XXVII, Fig. 65. 

 Metapeneiis qtiinqiiedejitatus J. G. de Man, in : Notes from the Leyden Museum, Vol. XXIX, 



1907, p. 133. 



Stat. 37. March 30/31. Sailus ketjil, Paternoster-islands. 27 m. and less. Coral and coralsand. 



I male and i female. 

 Stat. 99. June 28/29/30. 6°7'.5 N., 120° 26' E. Anchorage off North-Ubian. 16 — 23 m. Litho- 



thamnion-bottom. i male and i female. 

 Stat. 109. July 5/6. Anchorage off Pulu Tongkil, Sulu-archipelago. 13 m. Lithothamnion- 



bottom. I male. 

 Stat. 164. August 20. i°42'.5 S., i30°47'.5 E. Near West New Guinea. 32 m. Sand, small 



stones and shells. i young damaged female. 

 Stat. 184. September u/12. Anchorage off Kampong Kelang, South coast of Manipa-island. 



36 m. Coral, sand. 4 males and 2 females. 



71 



