45 



(1) Tlie carapace instead of being profusely spiny has a few large defi- 

 nitely placed spines, hence the orbital margin is not so spiny. 



(2) The vertically deflexed interantennulary spine is simple. 



(3) The rostral spines are shorter. 



I very much doubt whether these characters are of generic value ; and I 

 think that if adults of all three forms could be compared, both Cyrtomaia and 

 Echinoplax would be placed under A. MUne Edwards' genus Ergasticus. 



Cyrtomaia suhtni, Miers, var. 



Cyi-^omaiti sufcm;, Ifiers, Challenger Bracliyara, p. 16, pi. iii- fig. 3: Mary J. Rathbun, P. U. S. Nat. Mas. 

 XVI. 1893 (189-1), p. 230. 



This species was described from a damaged male dredged by the Challenger 

 in 500 fms., between the Philippines and Moluccas. Our specimen, which is a 

 male in good enough preservation, was dredged in 430 fms., off the Travancore 

 coast. It differs from the description of the type in the following characters :— 



(1) There is a third spine, much smaller than the other two, and standing 

 in the middle line, on the gastric region. 



(2) On the cardiac region, instead of a single spine, there are two spines 

 standing on a common tubercle. 



(3) The last abdominal tergum is quite smooth. 



These slight differences hardly warrant a specific designation. 



Plattmaia, Miers. 



Platymaia, Miers, 'ChaUenger' Brachynra, p. 12. ? : Alcock, J. A. S. B., Vol. LXIV. pt. 2, 1895, p. ISO. 

 <f k %. 



Carapace sub-orbicular. Rostrum short, tridenla,te owing to the size and 

 projection of the interantennulary septum. No pre-ocular spine ; but a post- 

 ocular spine against which the eye is retractile, but which affords no conceabnent 

 to the eye. Epistome extremely narrow. Eyes large, with short eye-stalks. 

 Basal antenna-joint short, cylindrical, and perfectly free : the flagellum and part 

 of the peduncle visible from above. 



External maxillipeds with the meropodite narrow, and bearing the next 

 joint at its summit. CheHpeds in the male long, with a long inflated club-shaped 

 palm : in the female very short and slender. Ambulatory legs long, with re- 

 markably thin compressed joints : some of the legs spiny. 



Abdomen in both sexes with all the segments separate. 



This genus appears to be very closely related to Macrochira. 



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