i68 



Records of the Indian Museum. 



[Voi,. XXIV, 



As a primary character in dividing the large number of species 

 which the subgenus contains I have employed the presence or 

 absence of a spine or tooth at the distal end of the merus of the 

 second peraeopod. De Man has found that a similar character in 

 the third peraeopod is of great value in the genus Alfiheus. I 

 think it probable that a primary separation on these lines is at 

 least as likely to demonstrate the true relationships of the species 

 as any other, but the principal specific characters are combined in 

 so many different ways that it is impossible in the present state of 

 our knowledge to determine which indicate affinity and which are 

 examples of convergence. The key which follows must therefore 

 be regarded as artificial. 



Key to the species of the subgenus Ancylocaris. 



Section I. Merus of second leg without a spine or tooth at distal end of 



lower border. - 



A. Supra-orbital spine present [hepatic spine pre- 

 sent]. 

 B. Cornea hemispherical. 



C. Rostrum shallow ; merus of second leg longer 



than carpus; R. 9 : 4 ... 

 C". Rostrum deep ; merus and carpus of second 

 leg subequal ; R. 7; 3.. 

 B' . Cornea conoidal, more or less pointed distally. 

 C. Rostrum not reaching end of antennular 

 peduncle. 



D. Eye with conspicuous terminal papilla ; R. 

 4:0 ... ... ... .. 



D' . Eye without conspicuous terminal papilla ; 



R.7=I * 



C. Rostrum reaching beyond end of antennular 

 peduncle [eye without conspicuous terminal 

 papilla]; R. 6 : I 

 A'. Supraorbital spine absent. 

 B. Hepatic spine present. 



C. Rostrum reaching far beyond end of scale ; 

 carpus of second leg twice as long as chela ; R. 

 6:0 ... ... 



C . Rostrum not reaching beyond end of scale ; 

 carpus of second leg little if at all longer than 

 chela. 



D. Second legs excessively long, ischium almost 

 reaching end of scale (? in males only) ; 

 ringers of second leg scarcely one quarter 

 length of palm ; R. 7 : o 

 D' . Second legs rarely long, ischium not nearly 

 reaching end of scale ; fingers of second leg 

 at least one-third as long as palm. 

 E. Carpus of second leg more than half as 

 long as palm. 



F. Distal spine of antennal scale reaching 



to or beyond end of lamella. 



G. Carpus of second leg conspicuously 



longer than palm ; dactylus of last 



three legs nearly one half as long as 



propodus. 



nilandensis Borr. 

 edivardsi (Paulson). 



cerat'jphthalmus Borr. 

 curnutiis 1 Borr. 



ambuinensis, 1 de Man. 



psuiiKitlie (de Man). 



lougipes (Stimpson). 



I In this species the second legs are unknown; it is assumed from its struc- 

 tural resemblance to P. ceratophthalmus that it falls in this section of the genus. 



