lOO 



London, a young male long 70 mm., in which the two branches of the petasma are still 

 separated and not yet fully developed. Except the fascinating blue colour, this specimen bore 

 such a strong resemblance, even in minute particulars, to the two specimens of P. seinisulcatus 

 de Haan from Djeddah, Red Sea, that are lying before me, together with the adult type of 

 this species from Japan, that one should be inclined to regard the species from Nahoon River 

 merely as a variety of the common P. semisulcatiis. Contrary to the Rev. Stebbing I observed 

 a well developed exopod on both legs of the 5'^ pair, which is somewhat smaller than the 

 exopods of the preceding legs. The specimen was not dissected by me so that I am unable to 

 say whether the endopod of the first maxillae is indeed much more elongate than in de Haan's 

 species, as suggested by the english carcinologist. The Rev. Stebbing drew my attention to the 

 fact that the thelycum agrees with Kishinouye's figure for P. ashiaka, which is identical with 

 P. semisulcatus ^ but that the shell of P. caertileus is decidedl)- thin, while that of P. ashiaka 

 is described by Kishinouye to be rather thick. 



I will finally add that, according to this Japanese author, P. as/iiaka has a greyish 

 brown or bluish colour. 



General distribution: Japan (de Haan, Ortm.\nn, Kishinouye, Rathbun); off Panay, 

 Philippine Islands (Spence Bate) ; South of New Guinea (Spence Bate) ; Java Sea (de Man) ; 

 Makassar (de Man); Singapore (Ortmann, Nobili); Orissa and Ganjam, off Indus Delta, Gulf 

 of Martaban, off Pulicat (Madras), Madras and Pondichery, Suez (Alcock, when, as I suppose, 

 this author's P. monodon is indeed identical with this species); Djeddah, Red Sea (de Man); 

 Aden (Nobili). 



43. PetiaeJts gracilirostris Thallw. 



Penaens gracilirostris J. Thalhvitz, Decapoden-Studien, Berlin 1891, p. 3, Fig. 5. 



Though this species was not collected by the "Siboga", the following observations will, 

 I suppose, be welcome. By the courtesy of Prof. K. M. Heller of the Royal Zoological Museum 

 at Dresden, I was enabled to examine the single type specimen oi Penaeus gracilirost7'isT\\d\\\\. 

 from North Celebes. This species has been quite well described, but, as regards the figure, 

 I wish to remark that not the y^, but the 4"' tooth of the upper margin of the rostrum is 

 placed above the orbital margin of the carapace, because, as is stated in the description, the 

 three first teeth are situated on the carapace. The distance between the two teeth of the 

 lower margin appears in the figure a little too long when compared with the distance between 

 the anterior tooth of the lower margin and the tip of the rostrum: in the type specimen, indeed, 

 the latter distance appears decidedly longer than the interspace between the two teeth. The 

 rostrum appears, between the teeth of the lower margin, distinctly higher than just beyond the 

 anterior tooth, because the rostrum regularly narrows towards the tip in a lateral view, but 

 this is not the case in the figure. Finally, the lateral rostral carinae that are a continuation of 

 the distal unarmed part of the upper margin, though distinctly extending behind the first tooth, 

 do not reach as far backward as the cervical groove, while they do so in the figure. 



This species now mostly approaches to P. seinisulcatus de Haan, that also occurs in the 



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