Carcinological Fauna of India. 



237 



The external maxillipeds have the merus as wide as or much wider 

 than the ischium, and the palp inserted at the antero-internal angle of 

 the merus. 



The rostrum is formed of two spines, which may be horizontal, 

 semi-deflexed, or completely deflexed ; in the last case the spines are 

 usually more or less fused together. 



The ambulatory legs are of no great length. 



Key to the Indian genera. 



Alliance 1. Maioid- 

 a. — C arapace 

 either regularly 

 pyriform or sub- 

 circular : rostral 

 spines horizontal : 

 orbits incomplete 

 below ; but fairly 

 well roofed in 

 above (1) by a su- 

 pra-ocular eave, 

 which has at least 

 its postero-exter- 

 nal angle pro- 

 duced, (2) by a 

 post-ocular spine, 

 and (3) by a spine 

 intercalated 

 between (1) and 

 (2). 



. Supra-ocular fi 

 eave and interme- 

 diate spine very 

 prominent : eye- 

 stalks slender and J 

 curved, with the ' 

 cornea elongate 

 and occupying a 

 positionmore ven- 

 tral than terminal. 



The antennulary 

 flagellum springs, 

 or appears to 

 spring, from with- 

 in the orbit ,. Maia. 



ii. The antennulary 

 flagellum arises 

 quite clear of the 



^ orbit 



Paramithrax. 

 [Chlorinoides.] 



Supra-ocular 

 eave and interme - 

 diate spine dis- 

 tinct, but not very 

 pr omine nt : e y e - 

 stalks stout, with<{ 

 rounded cornese 

 which occupy a 

 position as much 

 terminal as ven- 

 tral. 



Carapace p y r i - 

 form : rostral 

 spines of consider- 

 able length, and 

 with one or more 

 accessory spines 

 on the outer sur- 

 face 



Schizophrys. 



I 



, Carapace subcir- 

 cular : rostral 

 spines simple, and 

 so short as to 

 hardly break the 

 general outline of 

 the carapace C ycl ax. 



Alliance 2. Stenocionopoida. 

 — Carapace pyriform, often 

 broadened anteriorly : the 

 orbits either have the form 

 of long semitubular antlers 

 which sheathe the eye-stalk, 

 bat do not protect the eye, 

 the cornea in retraction being 

 protected by the base of an 

 extremely long and promi-<J 

 nent, isolated, post-ocular 

 horn ; or are reduced to the 

 form of long outstanding 

 horns similar to those of the 

 rostrum : eye-stalks extreme- 

 ly long: the external maxilli- 

 peds have the external angle 

 much produced : the rostrum 

 consists of two long horns. (. 



83 



. Orbits in the form of huge 

 semi-tubular antlers followed 

 by a long isolated post-ocular 

 tooth : rostrum vertically 

 deflexed : buccal frame much 

 broader in front than behind. 



Criocarcinus. 



2. Orbits in the form of long 

 outstanding horns similar to 

 those of the rostrum, which 

 is not deflexed, buccal frame 

 quadrangular Stenocionops. 



