lOI 



seas of North Celebes, but it is distinguished by the following specific characters ; The different 

 shape and characteristic toothing of the rostrum, that has a more slender form, while the teeth 

 of the upper margin are smaller, i. e. less high than in P. semisulcatjis. The post-rostral crest 

 is not grooved. Both in P. scuiisu/catns and in this species the lateral rostral carinae extend 

 a short way beyond the first tooth, different from /\ carinatiis Dana, but in P. semisulcahis 

 they reach farther backward than the cervical groove, whereas in P. gracilirostris the latter 

 extends a little farther backward than the lateral carinae. In P. semi.mlcatus the upper half of 

 the cervical groove is straight, directed obliquely upward, with the upper extremity situated 

 ju.st below the tip or at most below the free part of the first tooth, the groove presenting only 

 one posterior curve; in P. gracilirostris, however, the cervical groove has a S-like form, 

 because the upper half is not straight, but curved backward, and the upper extremity is situated 

 far behind the i^' tooth, that is distinctly indicated in the figure. The ridge that defines the 

 antennal groove above, is just as long as in P. semisulcatus and the subhepatic crest, which 

 is quite straight in the species of de Ha.\n, appears, in P. gracilirostris, very slightly arcuate, 

 which is also visible in the figure. In both species the s"" legs bear a small exopod, much 

 smaller than those of the preceding legs, but the 4'h and the 5'^ legs, especially the carpal 

 joints, show a somewhat more slender form in P. gracilirostris. 



The type specimen is a young male, in which the two branches of the petasma are not 

 yet quite developed and not yet united. Probably the petasma and the thelycum, like also the 

 oral appendages, will show still other differences. 



P. gracilirostris Thallw. seems to be a rare species, for it is still only known by one 

 single specimen ! 



44. Pe7iaeus carinatiis Dana. 



Penaeus carinatiis J. D. Dana, U. S. Explor. Exped. Crustacea, p. 602, PI. 40, Fig. 2. 

 Penaeiis semisulcatus ]. G. de Man, in: Journal Linnean Soc. London, Vol. XXII, 1888, p. 284 



and in: Max Weber's Zooi. Ergebn. 1892, p. 510 (partim). 

 Penaeus nionodoii J. R. Henderson, A Contribution to Indian Carcinology, London, 1893, p. 447. 

 Penaeus nionodon J. G. de Man, in: Zool. Jahrb. X. Abtli. f. Syst. 1898, p. 677. (the specimens 



examined). 

 Penaeus monodon K. Kishinouye, in: Journal Fisheries Bureau, Vol. VIII, N" i, Tokyo, 1900, 



p. IS, PL n, Fig. I and PI. VII, Fig. 3, 3 A. 

 Penaeus monodon G. Nobili, in: Boll. Mus. Zool. Torino, N" 452, 1903, p. i and X" 455, 



1903, p. I. 

 Penaeus semisulcatus A. Alcock, Catal. Indian Decap. Crustacea. Part III. Macrura. Fasc. 1, 



Calcutta, 1906, p. 10, PI. I, Fig. 2. 



Stat. 71. May 10 — June 7. Makassar. Depth up to 32 m. Mud. Sand witli mud. Coral. 4 



adult females. 

 Stat. 323. F"ebruary 24/25. Sangkapoera-roads, Bawcan-island. 12 m. Mud. i young male. 



These specimens certainly belong to the species which in Col. Alcock's valuable Monograph 

 of the Indian Prawns of the Peneus group has been described as P. semisulcatus de Haan, — 

 erroneously, however, as I pointed out on p. 97. In the present species there is no trace of an 

 exopod on the 5''^ legs, while in P. semisulcatus de Haan these legs bear a well developed 



