1907-] Records of the Indian Museum. 11 



as far forward as the level of the rostral base. The postero-lateral 

 angles are smoothly rounded. 



The first free thoracic segment bears two lateral spines, a long 

 anterior one, curving downwards and forwards, and a short posterior 

 blunter spine proj ecting transversely outwards ; there are no ventral 

 spines. The second free thoracic segment has a bilobed lateral 

 margin, the anterior lobe being smaller and more pointed than the 

 posterior. The lateral margin of the third thoracic segment is also 

 bilobed, the anterior lobe being much the smaller. 



Excepting the first, each of the free thoracic segments bears 

 four carinse, the sub median ones being somewhat obscure. All the 

 abdominal segments excepting the last bear eight carinae, the sub- 

 median pair are obscure. On the upper surface of the second to 

 the fifth abdominal segments there is a small dorsal tubercle which 

 is duplicated by a transverse groove. The lateral carinae of the first 

 to the sixth, the sublateral carinae of the third to the sixth, and the 

 submedian carinae of the fifth and sixth end in a spine posteriorly. 



The length of the telson is slightly greater than its breadth. 

 The margin bears four large spines, a pair of submedian and 

 a pair of sublateral ; anterior to each sublateral are two lesser mar- 

 ginal spines, the posterior of these bears a small tubercle at its 

 hinder angle. Between the submedian spines there are 8 to 10 

 teeth. Between the submedian and sublateral spines on each 

 side there are 9 to 10 teeth. The telson bears a mid-dorsal ridge 

 and a ventral tuberculated keel, the dorsal ridge ends posteriorly 

 in a spine, beneath which there are, in some specimens, two or 

 three other spines. At the anterior end of the dorsal ridge is 

 another blunt spine. The basal prolongation of the uropod is 

 finely serrated on its inner margin, the inner division is by far the 

 larger and bears a sharp spine in the middle of its outer edge. 

 The proximal joint of the exopodite is a little longer than the 

 distal and bears seven moveable spines on its outer border. 



(Up to this point in the description this species differs only 

 on minor points from 5. nepa, S. stridulans and several other 

 species.) 



In the raptatorial claw we find the most distinctive feature. 

 The dactylus bears about fifteen long, delicate curved teeth, the 

 number varying within wide limits. The number of teeth in sixteen 

 counted specimens was as follows : — 13, 17, 16, 16, 14, 18, 14, 14, 

 13, 10, 16, 13, 17, 15, 17, 16. 



This variation has no relation to sex. Not only does the num- 

 ber vary, but the length of the teeth and the amount of their 

 curvature is very variable. 



The opposing border of the propodite is finely serrated and 

 bears three moveable denticles near its base ; of these the middle 

 one is much the smallest. The carpus bears three stout blunt 

 spines. The posterior angle of the claw, when folded up, does 

 not reach as far as the posterior angle of the carapace. 



Numerous specimens ; sexes about equally distributed. 



Colour — Very variable, thorax and abdomen sand-colour with 



