RATHBUN— MARINE BRACHYURA 251 



gaping in the basal half, the immovable finger bowed downward ; a tooth near the base 

 of the dactyl ; both fingers minutely denticulated. Dactyli of legs entire. 



In the $ the horns are proportionally shorter, and in the $ and undeveloped $ the 

 chelipeds slenderer, the fingers nearly meeting at base. 



Dimensions in mm. : 



$, Sta. E 6, C. 1. med. 15-5, C. 1. entire 19-3, C. b. 10-4, Horns 1. 4*2, Ch. 1. 17-8, 

 W. L. 1. 1. 28. 



?, Sta. E 6, C. 1. med. 13"8, C. 1. entire 16, C. b. 9-2, Horns, 1. 2*4, Ch. 1. 12'2, 

 W. L. 1. 1. 18-6. 



The species has great resemblance to H. irami Laurie*, which is also unarmed, but 

 has a tooth on the orbital border between the preocular and postocular lobes, and horns 

 half as long as the rest of the carapace. 



The "small and young female dredged [by the Challenger^ at the Philippines in 

 18 fathoms, lat. 11°37'0"N., long. 123°31'0"E. (Station 208)" and referred by Miersf 

 to Hyastenus diacanthus, is probably Halimus inermis. The orbits, antenna? and 

 pterygostomian region are similar to those of H. diacanthus, but the latter has subparallel 

 horns, and tubercles and spines on the carapace ; moreover it is a large species while 

 H. inermis is a small one. 



217. Halimus elongatus Ortmann. 



Hyastenus diacanthus Miers, Proc. Zool. Soc. London, 1879, p. 26 (part; immature $, 

 near Cape Sima, 18 fathoms). 



Hyastenus diacanthus var. elongata Ortmann, Zool. Jahrb. Syst., vii. 1893, p. 55. 



Amirante, 29 fms., Sta. El; I $ (a): 34 fins., Sta. E9; U (b), 1 ? juv. 



The largest male (a) is only 9 - 3 mm. long, 6 mm. wide, has one horn completely broken 

 off and the other broken not far from the base. The carapace is more oblong than in 

 H. diacanthus, and is without spines or tubercles except a vestige of one on the summit 

 of the gastric region; setaa awl-shaped. Orbital and antennal region similar to that of II. 

 diacanthus. The chelipeds have the appearance of belonging to an adult ; palm twice as 

 long as wide, a tubercle at the middle of the upper margin ; fingers gaping for half their 

 length, dentate, the proximal tooth of the dactyl being slightly larger. Dactyli of legs 

 armed with spines visible to the naked eye and increasing in size toward the tip of the 

 dactyl. 



(b) is 9*1 mm. long, 5 6 wide, horns 4*2 mm. 



218. Halimus borradailei Rathbun (Plate 20, fig. 5). 



Halimus borradailei Rathbun, Mem. Mus. Com p. Zool., xxxv. 1907, p. 64. 



Cargados Carajos, 28 fms., Sta. B 20 ; 3 $. Amirante, 20 — 25 fms., Sta. E 13 ; 

 1 ? ovigerous. 



The female is larger than that taken at Funafuti, but considerably smaller than 

 Borradaile's figured specimen from Rotuma. 



* In Herdman, Ceylon Pearl Fisheries, pt. v, Suppl. Rept. XL, Brachyura, 1906, p. 379, pi. 1, ligs. 4, 4 a. 

 t Challenger Brachyura, 18SG, p. 57. 



