271 



At the first locality it was found associated with Fishilana clava (a boring Lamellibranch), at 

 the second in the tubes of an AnneHd. The "Siboga" specimen was found at this latter locality, 

 bat, like that of Alcock from the Andamans, it was apparently freely living on the coral reef. 

 Dimensions in mm. : 



Fronto-orbital distance 4. — 



Breadth of carapace 8. — 



Length of carapace 5.7 



Length of penultimate pair of legs .... 8.8 



Length of last pair of legs 4.35 



Distance between bases of last pair of legs . 6.6 



Breadth of abdomen at base 2.15 



My specimen is about the size of that of Alcock. 



Subfam. Xenophthalminae. 

 This subfamily has been instituted by Alcock on a single genus. 



Xenophthalmus White. 



1846. Xenophthalmus White. Ann. Mag. Nat. Hist., v. 18, p. 177. 



As is well known, the genus is easily recognizable by the orbits, instead of being 

 marginal and transverse (or nearly so), being formed by 1 o n g i t u d i n a 1 slits in the carapace, 

 so that the narrow front is clearly defined laterally. An epistome is absent ; the external 

 maxillipeds are broad, parallel, ischium and merus equally long, joints of palp flattened, palp 

 somewhat spirally twisted, extremely slender, rod-like, concealed in outer view. Chelipeds, even 

 in Cf", very small and weak, much more so than the walking legs, the meropodits of which 

 are armed along their posterior margin with a row of spines. Abdomen of both sexes narrow, 

 consisting of seven separated segments. 



Four species in all have been assigned to the genus. Two of these, the type species 

 X. pinnotheroides White and A'. obsctirus Henderson are well established. A third species is 

 X. duplociliatus Sluiter '). This species, according to the description, resembles the type species, 

 but the chelipeds are much strenger, broadly-flattened and "lepelvormig gebogen" (shaped 

 like a spoon) ; besides the under surface of the posterior legs is brightly red, and the 3*^ and 

 4'^^ segment of the abdomen of the 9 is provided with a transverse row of long hairs. 

 Sluiter says that White mentions the presence of bristles at the 3'^ .segment of the abdomen 

 of the 9i but the latter author's words on this subject are: "a long ciliated process proceeding 

 from each end of the third joint". One cannot help thinking that White mistook the (bifur- 

 cated) pleopod of the O, reaching beyond the 3*^ segment, for this "ciliated process", for in 

 reality the abdomen of the 9 does not show any prominences on its exposed surface or on 

 its borders. 



l) Natuurkundig Tijdschrift Xed. Indië, 1)1. 40, 1881, p. 163. Hab. harbour of Tandjong Priok (Batavia). 



