Care biological Fauna of India) 261 



85. Nursilia tonsor, n. sp. 



This species is distinguished (1) by its smaller size, — ovigerous 

 females having the carapace only 7 millim. long and 725 millim. broad, 

 and adult males being a good deal smaller : (2) the gastro-cardiac region 

 is defined posteriorly on either side by an oblique dentigerons l'idge, 

 which meets the oblique ridge that traverses either branchial region at 

 an obtuse angle — the whole forming a sharply defined W reversed: 



(3) the hand is less swollen and the outer edge of the fingers is cristi- 

 form — the cristiform lamina being of extreme thinness and delicacy : 



(4 ) the serrations of the lateral margins and the ridges and spines of 

 the carapace are all much sharper-cut. 



Loc. Andaman Sea up to 40 fms., off Ceylon 34 fms. 



Heterolithadia, Wood -Mason, (name only). 



Carapace broader than long, transversely somewhat oval, its surface 

 nodular, coarsely granular, convex except the hepatic regions which 

 are hollowed ; all the regions well delimited by grooves. 



Front distinct, moderately pi'ominent, broadly bidentate. Orbits 

 with very indistinct sutures in the outer wall, and with very little 

 space between their lower edge and the edge of the buccal cavern. 

 The antennules fold obliquely. The antennas have a short flagellum 

 and occupy the much restricted space between the antennules and the 

 eye. 



Buccal cavern triangular with the sides curved somewhat as in 

 Nursilia : merus of external maxillipeds half the length of the ischium 

 measured along the inner border. 



Chelipeds stout, about half again as long as the carapace : hand 

 very short, swollen, half the length of the fingers : fingers slender, of 

 nearly the same diameter from base to near the hook-like tip, opening 

 in a nearly vertical plane, the tip of the dactylus being movable 

 through an arc of about 75°. 



The abdomen of the male has the 3rd-6th segments fused. 



Heterolithadia has a strong external resemblance to Lithadia, but 

 has the Ilia fingei's and external maxillipeds. Its nearest ally is 

 Nursilia. 



86. Heterolithadia fallax, (Henderson). 



Ebalia fallax, J. R. Henderson, Trans. Linn. Soc, Zool., (2) V. 1893, p. 402, 

 pi. xxxviii. iigs. 4-6. 



The posterior half of the carapace is a segment of a broad ellipse, 

 the anterior half is broadly triangular. 



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