no Memoirs of the Indian Museum. [Vol.. IV, 



includes L.maculata, the only common Indo-pacific representative of the genus, and 

 three species described from unique specimens. One of the latter, L. crassispinosa, 

 Fukuda, furnished with a remarkably large number of movable spines on the pen- 

 ultimate segment of the raptorial claw, appears to be an isolated form, but may perhaps 

 find allies among the less well-known Atlantic species. The typical representative of 

 the second group is L. acanthocarpus. L. insignis and L. latifrons form a small highly 

 specialized section characterized by the elaborate ornamentation of the telson, while 

 L. spinosa, in which the inner spine of the ventral process of the uropods is suppressed, 

 seems to have no close affinity with any other known species. 



Practically nothing is known of the habits of Indo-pacific species of Lysiosquilla. 

 Brooks, however, notes that those of L. excavatrix are very different from those of 

 Squitta empusa, and it is probable that his observations afford an explanation of the 

 extreme scarcity of many species. L. excavatrix inhabits much deeper burrows than 

 S. empusa ; it lies in wait for its prey at the mouth of the burrow and seldom ventures 

 more than a few inches away. Squitta empusa on the contrary wanders about and is 

 in consequence caught without much trouble. The burrows of L. excavatrix extend 

 vertically downwards for a distance of several feet and Brooks found it almost im- 

 possible to obtain them by digging. Under these conditions it will readily be under- 

 stood that the difficulty of obtaining specimens is very great and when the species 

 inhabits comparatively deep water, as some are known to do, it can only be by the 

 merest chance that a specimen is caught at all. 



The greatest depth at which any species of the genus has been found is 235 

 fathoms (L. insignis). 



Many undescribed forms doubtless remain to be found and a number of those that 

 are already known stand in need of redefinition. 



Key to the Indo-pacific species of Lysiosquilla. 

 I. Telson without dorsal spines; limbs of sixth and seventh thoracic somites 

 with shorter ramus linear. 

 A. Upper margin of raptorial propodus with not more than four movable 

 spines; postero-lateral angles of first five abdominal somites not 

 spinous. 

 I. Raptorial dactylus with eight to eleven teeth. 1 



A. Exposed thoracic somites without longitudinal wrinkles; sixth 



abdominal somite not grotesquely sculptured; terminal 



tooth of raptorial claw not dilated at apex. 



r. Rostrum cordiform, at least as wide in front of base as at 



base, not grooved near margin; raptorial dactjlus with 



ten or eleven teeth ' in male . . . . . . maculata, p. in. 



2. Rostrum triangular, widest at base, with a deeply- incised 

 antero-lateral groove; raptorial dactylus of male with 

 eight teeth 1 . . . . . . . . do. var. sulcirostris, 



B. Exposed thoracic somites irregularly and longitudinally wrink- 



p. 116. 



Including the terminal tooth. 



