1898.] A. Alcock — Carcinnlogical Fauna of India. 233 



Platypilumnus gracilipes, Wood-Mason. 



Platypilumnus gracilipes, Wood-Mason MS., Alcock, Ann. Mag. Nat. Hist. May, 

 1894, p. 401 : 111. Zool. Investigator, Crust, pi. xiv. fig. 6. 



Carapace much depressed, perfectly flat above, with the surface 

 nearly smooth centrally and very finely and closely granular laterally, 

 and with the regions indistinctly defined. The front has the form of a 

 horizontally projecting bilobed lamella, with the free edge sharply and 

 very evenly spinate and the sides turned abruptly downwards. The 

 margins of the orbit are spinulate, the upper margin the more distinct- 

 ly so, and the lower margin terminates internally in a strong oblique 

 spine, the point of which inclines towards the sharply vertical tooth 

 formed by the already mentioned downfolding of the lateral edge of 

 the frontal lamella. 



The antero-lateral borders of the carapace which are arcuate and 

 are shorter than the postero-lateral, are armed with three large spines, 

 in front of, between, and behind which are several spinules. 



The pterygostomian regions are large and inflated, and the branchial 

 apertures, especially the efferent aperture, are large and patulous. 



The eye-stalks are large and are of moderate length ; the corneal 

 region is rather small. 



The antennules are long and are transversely folded, their basal 

 joint is large and inflated. 



The antennae are long, their basal joint is slender and free ; the 

 second joint lies loosely in the internal orbital hiatus. 



The inner edge of the meropodite of the external maxillipeds is 

 convex, with a pair of little spines at the summit of the convexity ; 

 the succeeding joint arises at the antero-internal angle. 



The thoracic legs are furnished with many spines and long hairs. 

 The chelipeds, which are robust, are unequal ; their prismatic arm 

 has all its borders spiny ; the short inflated wrist is sharply granular 

 and spinulate in the distal half of its dorsal surface and along the 

 outer edge, while the inner edge bears a pair of rather large spines ; 

 the hand is spinulate everywhere in the smaller cheliped, but only in 

 the proximal third of its outer surface in the larger ; the fingers also 

 of the smaller cheliped are spinulate on the outer surface, while those 

 of the larger cheliped are smooth ; the cutting-edges of the fingers are 

 finely and unevenly toothed. 



The other thoracic legs are long, compressed, and slender, and have 

 the meropodite spiny along both edges, the carpopodite and propodite 

 spiny along the front edge, and the dactylopodite styliform. 



Colour in the fresh state yellowish red. 



Andaman Sea, 188-220 fms. A single female. 



J. II. 30 



