1913-] S.Kemp: Crustacea Stomatopoda of the Indo-Paci fie Region, igy 



The fishermen spoke of a large species with similar colouring, doubtless Lysio- 

 squilla maculata ; no specimens, however, could be obtained. 



Gonodactylus glabrous, Brooks, [p. 167.] 



The species occurred in profusion on coral reefs both at Kilakarai and Pamban, 

 and at the latter place was also obtained on reefs exposed at low tide. The speci- 

 mens were, for the most part, found in crevices and holes in coral blocks and in these 

 situations examples of all sizes (from 7-5 mm. in length and upwards) were obtained. 

 Very small individuals were also caught by dragging a fine-meshed net through the 

 Zostera and other weeds which flourished inside the reef in water not more than one 

 or two feet deep. 



In specimens 7-5 mm. in length only the median carina of the telson is distinguish- 

 able, but in examples only 1 mm. longer all five are developed. Among the various 

 forms which the telson may assume in Gonodactylus chiragra, form A {—incipiens) most 

 nearly resembles G . glabrous, and according to Lanchester this form constitutes a true 

 connecting link between the two species. It is therefore noteworthy that no speci- 

 men was found on this occasion that can be referred to the variety and that even at 

 a very early age (specimens 8-9 mm. in length) the distinctions between G. glabrous 

 and G. chiragra form H are well-marked. In all G. glabrous exceeding 7*5 mm. in 

 length five carinae are developed, and of these five the submedians are invariably 

 longer than those of the pair external to them. 



Many females with egg-masses were found and this observation is one of some 

 interest seeing that it does not appear to have been made hitherto in Indo-pacific 

 waters. The females were found in the coral-masses in holes that appeared to have 

 been made originally by Lithodomus or some other rock-boring mollusc, the eggs, which 

 were of a bright greenish-yellow colour, lying at the bottom of the burrow in a loosely- 

 compacted discoidal mass. When disturbed the female rapidly gathered the eggs 

 into a ball and, holding them with her thoracic appendages, rushed wildly to and fro 

 seeking concealment or escape. Even the shock of sudden immersion in alcohol was 

 not always sufficient to induce the mother to lay aside her parental responsibilities. 

 The egg-masses varied, according to the size of the female, from 8 to 14 mm. in 

 diameter, individual ova measuring from 7 to -85 mm. 



The habits of the species appear to be closely similar to those of G. oerstedi, 

 observed by Brooks in the Bahamas ; but whereas the latter species is said to con- 

 struct burrows for itself in solid coral, G. glabrous seems merely to inhabit those made 

 by other animals. 1 In order to tunnel in hard rock an animal must needs be highly 

 specialized and consideration of the very close uniformity in structure in G. glabrous 

 and G. oerstedi leads one to believe that adaptation for such a purpose, if present 

 in one form, would certainly be present in the other. Although Brooks never saw 

 specimens engaged in tunnelling he had no doubt that the species actually made its 



1 Specimens were never found in new and clean-cut burrows, but only in those eroded and over- 

 grown with encrusting organisms. 



