236 Surg.-Capt. A. Alcock on 



shallow, with the inner edge finely granular ; the ophthalmic 

 peduncles have each a small scrobiculate spine at the frontal 

 level. 



The basal joint of the antennules, which is very large, has 

 a single spine at the antero-external angle, its scale is about 

 four times larger than the antennal scale, both ending in 

 spines. 



All five pairs of legs are perfectly chelate (in tlie female). 



The great chelipeds are not quite equal in length to the 

 body, and in armature are similar to those of P. gibha, the 

 meropodite being finely and distantly serrrated on both edges 

 and the propodite having the lower edge of the palm serrated. 



The first pair of abdominal appendages are relatively very 

 small, in the female. 



A female from the Bay of Bengal, Carpenter's Ridge, 

 1370 to 1540 fathoms ; it measures 87 millim. from rostrum 

 to tip of telson in the mid-dorsal line. 



The characteristic feature of this species is the remarkable 

 concavity of the frontal margin between the ophthalmic 

 notches and the consequent shallowness of the latter. 



67. Pentacheles Beaumontu*, sp. n. 



Carapace finely but distinctly granular; its greatest 

 breadth, just behind the middle, is three fourths the greatest 

 length ; tiie median carina is surmounted by a double row of 

 fine granulation and bears — (1) a double rostral spine, and 

 (2) four spines (of which the middle two form a pair) in the 

 front part of the gastric region, these being the only large 

 spines present ; the frontal margin has both the inner and 

 the outer angle of the orbital notches produced into large 

 spines, but is otherwise, except for the rostral spines, quite 

 smooth ; the smooth posterior margin (whicii, as usual, is 

 formed by the last thoracic tergum) is peculiar in being nearly 

 straight ; the lateral margins are peculiar in having the spines 

 of almost equal size throughout, these numbering on each side 

 23 or 24, namely 7 or 8 + 3 in front of the cervical groove 

 and 13 behind it; the dorsal sublateral (branchiostegal) 

 ridges arc sinuous, ver}' faint, especially in front, and faintly 

 denticulate, while of the two usual ridges that traverse the 

 branchial regions on the ventral aspect the most dorsad on 

 each side is apparent only in front of the cervical groove. 



The abdominal terga have the surface smooth or pitted ; 



* This species is figured iu " Illustrations of the Zoology of the Uoval 

 Indian Marino Steamer 'Investigator,' Criistacoa," pt. ii. (pl. viii.\ to be 

 issued early this yeai*. 



