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Antennal scale distinctly longer than the antennular peduncle, reaching almost by the 

 whole length of 3''' article beyond it. 



The external maxillipeds extend to a little beyond the middle of the scaphocerite, just 

 reaching beyond the extremity of basal antennular article. 



Of the I*' pair of legs both the coxa and the ischium are armed with a spine, of the 

 2°*^ pair the coxa alone, while the y^ pair is quite unarmed. The i**' pair of legs is of a 

 rather stout shape and reaches to the extremity of the antennal peduncle ; carpus a little longer 

 than the merus, chela nearly two-thirds as long as the carpus, fingers a little shorter than the 

 palm. Second legs a little longer and a little more slender than the i^', 3''^ slightly longer and 

 more slender than the 2°^^; the 3'^ legs project with the fingers almost beyond the eye-peduncles, 

 carous a little more than twice as lono; as the chela, fincrers almost two-thirds as long; as the 

 palm. The legs of the 4"^ and 5"^ pairs are almost equally long, the 4'^^ extend to the base 

 of the carpocerite, the 5* are hardly shorter and reach to the distal extremity of the car^aus 

 of the i>'. All the legs, also these of the 5* pair, bear an exopod. 



A pair of well developed slender spines between the legs of the 2""^ pair. A single median 

 acute spine situated on a transverse prominence between the bases of the feet of the 4"^ pair; 

 this prominence is united posteriorly by a short, median, longitudinal ridge with the posterior 

 part of the thelycum. This posterior part, deeply grooved in the middle, is bilobate and consists 

 of two almost circular lobes that are rounded anteriorly and the outer surface of which is slightly 

 convex. The posterior part of the thelycum is situated between the legs of the last pair and is 

 bounded posteriorly by a narrow ridge, on the middle of which 5 or 6 setae are inserted. 



The largest specimen is nearly 56 mm. long. 



Rem ark s. The japanese Pen. Dalei (Rathb.) and acclivis (Rathb.) are closely related 

 species but are distinguished, at first sight, by the different form of the thelycum. Yery closely 

 allied is, no doubt, also Pen. coiniiicnsalis (Borr.) (L. A. Borradaile, in: Proc. Zool. Soc. 1898, 

 p. lOOi, PI. LXIII, Figs. I — I ^), a species which, on the coast of the island of Rotuma, is 

 living in a green and yellow Actinian, but of which unfortunately the female is unknown. As 

 Dr. Borradaile informed me, the single type specimen of this Pen. comiuensalis does not 

 more exist in the Museum at Cambridge and he fears it must have been lost. Dr. Borradaile 

 to whom I sent the specimen from Stat. 131 for examination, was, however, inclined to think 

 that the ".Siboga" species is not Pen. coiuiiicnsalis and I am of the same opinion. In the 

 species from Rotuma, indeed, the antennular peduncle is longer than the scaphocerite, in the 

 "Siboga" species shorter than it and the rostrum is horizontal, not ascending; the 6* abdominal 

 somite, finally, appears, in the figure, comparatively much longer, more than three-fourths as 

 long as the carapace. 



In a paper on the Penaeidae, published September 1881 in "The Annals and Magazine 

 of Natural History", a Penaeiis Pliilippii from the Philippine Islands was described by Spence 

 Bate, a species not mentioned by Dr. Alcock in his useful "Revision of the "Genus" Pcneiis' 

 (ibidem, Ser. 7, Vol. XVI, 1905). This species also seems to be related to Pen. Borradailei^ 

 but the antennular peduncle of Pen. Philippii is not longer than the rostrum and the latter 

 bears only 6 or 7 teeth ; the antennular flagella are half as long as the peduncle. Unfortunately 



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