277 



Stat. 282. January 15/17. 8°25'.2S., i27°i8'.4E. Anchorage between Nusa Besi and the N.E.- 



point of Timor. 27 — 54 m. Sand, coral and Lithothamnion. i specimen of 



medium size. 

 Stat. 315. February 17/18. Anchorage East of Saikis Besar, Paternoster-islands. Depth up to 



36 m. Coral and Lithothamnion. i ova-bearing female of medium size, lodging 



a Bopyrid in the carapace, and 3 young specimens. 



A new species of the Biungtiictdatus group, closely related to Syn. pachymeris Cout. 

 from the Western Indian Ocean, but at first sight distinguished from this and perhaps from 

 all other species of this genus, excepting Syn. Pescadorensis Cout. and Syn. septemspinosus 

 de Man, by the anterior margin of the palm of the large chela terminating in two conical 

 tubercles placed abreast. Thanks to the kindness of Professor Coutiere a specimen 

 of Syn. pachymeris, from Saya de Malha (Percy Sladen Trust Expedition) and determined by 

 him, is lying before me. The four specimens from Stat. 164, the largest of which, an egg- 

 bearing female, is 21,5 mm. long, have lost the large cheliped, therefore one of the specimens 

 from Stat. 273, a male long 12,5 mm., will be described as the type. 



The rostrum is slender, five times as long as wide in the middle, the acute tip is curved 

 upward and reaches to the middle of the visible part of first antennular article; the rostrum is 

 carinate above and the rostral carina extends to the posterior end of the eyes. Lateral spines 

 triangular, acute, one-third shorter than the rostrum, reaching to the 2"'' third of the visible 

 part of basal article, slightly setose at the tips that are not curved upward, with the outer 

 margin slightly concave and separated from the rostrum by wide intervals, obtuse at the base. 

 Second article of antennular peduncle one and a half as long as wide distally, measuring two- 

 thirds the visible part of basal article and one-third longer than the third article, the proportions 

 of the three articles being as 6:4:3. Stylocerite slender, acuminate, reaching to the second 

 ^id or 4"! part of median article. Basicerite with the upper spine well developed, the acute tip 

 directed upward and outward; lateral or inferior spine slender, longer than the stylocerite, 

 reaching to the middle or just beyond the middle of median article, with the acuminate tip 

 slightly turned outward. The carpocerite is slender, 5,5-times longer than wide, e.xceeding 

 the antennular peduncle by the whole length of the third article ; terminal spine of scaphocerite 

 a little shorter than the carpocerite, but still much surpassing the antennular peduncle, its outer 

 margin slightly concave, but not curved inward at the tip; it exceeds by half its length the 

 very narrow scale that reaches to the apex of median antennular article. 



The telson, the measurements of which are found in Table A, resembles that of Syn. 

 pachymeris. The length equals 3 — 3,24-times the width of the posterior margin and in both 

 species the anterior pair of spinules are situated far before the middle; the posterior 

 margin, however, is less prominent than in Syn. pachymeris and in the latter the spinules of the 

 upper surface are inserted nearer to the lateral margins. Outer angles of the posterior margin 

 acute, though very short. In the young male from Stat. 282 the telson appears a little shorter 

 with regard to the width of the posterior margin. 



Posterior angle of first abdominal pleura produced, in the male, into a small tooth, the 

 following also acute while in the third and the fourth the anterior angle is also sharp. 



Merus of large cheliped of the male twice as long as wide, with a small, acute tooth 



145 



SIBOGA-EXPEDITIE XXXIX n'. l6 



