79 



tooth in which the thickened outer margin terminates, the i st pair of legs do not reach beyond 

 the antennal scale and the propodi of the following legs are apparently slightly longer. In order 

 to establish with certainty the slight differences existing between the type species and these 

 varieties, it should, however, be necessary to compare several specimens from the various 

 localities where they are found. 



General distribution: The variety producta Bate, which in the Report on the 

 Challeno-er Macrura was described as a proper species, was obtained by the Challenger expedition 

 near Yokohama, Japan, off Luzon, Philippine Islands, off Banda Island and off the New Hebrides. 



2. Nematocarcinus tenuirostris Bate var. Sièogae de Man. PI. VIII, Fig. 19 — 19^. 



Nematocarcinus tenuirostris Sp. Bate, var. sibogae J. G. de Man, in: Zoolog. Mededeelingen, 



uitgegeven vanwege 's Rijks Museum van Natuurlijke Historie te Leiden, Deel III, Afl. 4, 



Dec. 1917, p. 279. 

 Nematocarcinus tenuirostris C. Spence Bate, Report Challenger Macrura, 1888, p.817, Pl.CXXXII, 



Fig. 10. 

 Nematocarcinus tenuirostris A. Alcock, Catal. Indian Deep-Sea Crustacea. Decap. Macrura 



and Anomala in the Indian Museum, Calcutta 1901, p. 88. 

 Nematocarcinus tenuirostris M. J. Rathbun, The Brachyura and Macrura of the Hawaiian 



Islands, Wash. 1906, p. 926, PI. XXIII, Fig. 6. 



Stat. 300. January 30. io°48'.6S., I23°23'.i E. 918 m. Bottom fine grey mud. 4 adult females, 

 3 of which are egg-bearing. 



In the typical Nemat. tenuirostris, as described by Spence Bate and Miss Rathbun, the 

 rostrum is from two-thirds to one-half as long as the rest of the carapace, projecting horizontally 

 forwards, with the upper margin slightly convex (M. J. Rathbun, 1. c. fig. 6) and with 9 — 13 

 dorsal and 1 or 2 ventral teeth. In the adult specimens, collected by the "Siboga" off the 

 south coast of Rotti, the rostrum measures, however, somewhat more than two-thirds 

 the length of the carapace proper and is more or less obliquely turned upward from 

 the orbital margin to the tip; it is styliform, gradually tapering, quite straight, not at all 

 convex in front of the eyes and armed on the upper margin with 8 — 10 teeth, on the lower 

 with one and of the dorsal teeth 4 are constantly placed on the carapace posterior to the 

 orbital margin. It is on account of these differences that these specimens are considered by me 

 to belong to a distinct variety which is also found in the Gulf of Manar and the Bay of Bengal, 

 because the species described by Col. Alcock did no doubt agree with our specimens from off 

 the south coast of Rotti. Unfortunately Miss Rathbun, who had the opportunity of examining 

 275 specimens of this species, does not indicate the length of the body, but, according to Spence 

 Bate, the female of the typical species should be 87 mm. long, but perhaps were the 7 specimens 

 of the "Challenger" not yet full-grown. The largest specimen, measured by Alcock, was 1 17 mm. 

 long, the length of our specimens varies between 119 and 146 mm. from tip of rostrum to tip 

 of telson. Three females are egg-bearing, the fourth, which is the smallest of all, is not yet 

 ovigerous, but it is certainly a female, because the pleopods of the 2 nd pair bear only one 

 appendix and no additional one. In this youngest specimen, that is, however, 119 mm. long, 

 the 5 thoracic legs are all preserved, but in the three others they are wanting, except those 



