70 A. Alcock — Carcinological Fauna of India. [No. 1, 



Carapace transversely oval or transversely hexagonal or subquad- 

 rate or (rarely) subcircular, but almost always broader than long. 

 Front broadish or very broad, never in the form of a rostrum. The 

 fold of the antennules is transverse or obliquely transverse. Antennary 

 flagella short or slender. Anterior margin of buccal cavern very well 

 defined, not overlapped by the external maxillipeds. Legs gressorial. 



The Xanthidse may be divided, according to the character of the 

 palate emphasized by Dana, into two sections, as follows : — 



I. Hyperomerista, in which the efferent branchial channel on either 

 side is defined by a ridge on either side of the palate, — the ridge extend- 

 ing right up to the anterior border of the buccal cavern. 



II. Hyperolissa, in which ridges defining the efferent branchial 

 channels are either altogether absent or are present on the posterior 

 part of the palate only. • 



I do not think that these sections, depending on a single variable 

 character, should be considered as families, or even as subfamilies. 



The section Hyperolissa, which corresponds to Dana's family 

 Cancrida3, minus Cancer andPiriraela and Polydectus, is here subdivided 

 into 3 subfamilies, hereafter characterized, namely, Xanthine, Actseime, 

 and Ghlorodinm. 



The section Hyperomerista, which corresponds to Dana's family 

 Eriphiidae, minus Oethra, is here subdivided into 4 subfamilies, hereafter 

 characterized, namely, Menippinse, Oziinse, Pilumninse and Eriphiinse. 



The genus Platypilumnus, Wood-Mason MS., Alcock, Ann. Mag. 

 Nat. Hist. May 1894, p. 401, and Illustrations of the Zoology of the 

 Investigator, Crustacea pi. xiv. fig. 6, probably belongs to this family 

 and to the section Hyperolissa, and is probably related most nearly to 

 Galene ; but as I have only a single female specimen to go by its exact 

 position must remain undecided. 



The following artificial key is meant to serve for the discrimination 

 of the Indian genera of this family :— 



