220 A. Alcock — Oarcirtological Fauna of India. [No. 2, 



3. The two red rings on the posterior half of the carapace are 

 often, but not always, much larger, and the six white spots on the 

 anterior part of the carapace are enclosed in six red circles, which 

 often partly coalesce to form a double trefoil pattern. 



In the Museum collection are an adult female, two half-grown 

 females, and a half -grown male, all from the Persian Gulf ; and the 

 characteristic trefoil pattern occurs only in the adult female. 



49. Leucosia urania, Herbst. 



Leucosia urania, Herbst, Krabben, III. ii. 17, pi. liii. fig. 3 : Leach, Zool. 

 Miscell. III. p. 21 : Desmarest, Consid. Gen. Crust., p. 167 : Milne Edwards, Cuv. 

 Regne An., Crust, pi. xxv. fig. 1, and ? Hist. Nat. Crust II. 122 : Bell, Trans Linn. 

 Soc. XXI. 1855, p. 283, and Cat. Leucos. Brit. Mus. p. 6: Hilgendorf, MB. Ak. 

 Berl. 1878, p. 811. 



This species, although closely resembling L. longifrons, and especi- 

 ally the variety (or species) neocaledonica, is at once distinguished from 

 these, and from all other species, by its comparatively great size. It is a 

 giant in the genus Leucosia, the carapace of an adult female in the Indian 

 Museum collection being 38 millim. long and 34 millim. broad, dimen- 

 sions almost equalled by Herbst's figure. 



It differs f torn L. longifrons only in the following particulars, adult 

 females being compared : — 



1. It is very much larger. 



2. The antero-lateral border is but slightly sinuous, owing to the 

 slight prominence of the hepatic regions, of which also the dorsal con- 

 vexities are an almost indistinguishable part of the general convexity of 

 the carapace. 



3. The hand is as broad as long, and the fingers have their 

 opposed edges crenulate throughout. 



4. The meropodites of the legs are traversed ventrally by a line 

 of granules. 



5. The propodites of the legs are foliaceous. 



6. The dactyli are broadly lanceolate, and are only equal in length 

 to their propodites. 



7. Colours (of a thoroughly well-preserved specimen that has been 

 eight years in spirit) olive green, with a broad white median band, 

 forked posteriorly, extending from the tip of the front to the after end 

 of the gastric region ; four dusky red blotches round the posterior half 

 of the circumference of the carapace : legs yellow, banded with red ; 

 basal half of fingers red. 



Loc. Andamans. 



The single female specimen in the Indian Museum collection is the 

 exact counterpart of Herbst's figure. 



