196 ox DIRECT DEVELOPMENT IX A DROMIID CRAB. 



llagellum, which appears to be doul^le, but owing to the brittleuess 

 of the dried specimen this couhl not be determined Avith certainty. 

 The antennfe consist of four joints, so far as can be made out, 

 with a squame and a flagellum, the squame being rudimentary 

 and similar to that in Cano's figure. 



Text-figure 8. 



Cheliped of post-iavval stage. 

 The abdomen is not extended and folded at the tip as in the 

 megalopa figured by Cano, but is tucked beneath the body in 

 typically Brachyurous manner. It bears four pairs of pleopods 

 similar to those of the adult ; the telson is also like that of the 

 adult, there being simply a trace of the sixth pleopod visible 

 between the 6th and 7th segments, and not, as in Cano's megalopa, 

 a distinct ramus on either side. 



The last two pairs of legs are distinctly cheliform, and not 

 weakly subchelate, as in the megalopa. 



Sternal grooves cannot be distinguished in the young, nor can 

 it be seen whether there is an epipodite on the cheliped. 



The young in this case are definitely post-larval, and the 

 growth-changes which occur before reaching maturit}^ are (a) the 

 broadening of the carapace until it is broader than long, (b) the 

 forward movement of the eye, (c) the effacing of the grooves 

 between the regions of the carapace, {d) the thickening of the 

 legs and chelipeds, and (e) the appearance of ridges on them. 

 The thorns and spinules of the young are generally absent in the 

 adult, which, on the other hand, in life was covered with a short 

 tomentum, which is not seen in the young. 



It is very extraordinary that in a well-known species such as 

 this, no record should hitherto have been made of the direct 

 development of a post-larval stage from the egg. The possibility 

 that the larvaj have hatched from the egg, and passed through zoea, 

 metazoea and megalopa stages clinging to the pleopods under the 

 abdomen of the female, may be ruled out for the reason that it 

 would be impossible for an ad equate food-supply to be maintained. 

 And, in fact, no record has been found of F. lateralis or 

 y. serpulifera having been captured with eggs, though this is a 

 common occurrence with other Oxyrhjaichs and Dromiids, 

 numerous examples being recorded in the collections both of the 

 ' Sealark ' * and the Ceylon Pearl Oyster Commission T. 



* Mary J. Rathbun, Trans. Linn. Soc. Loudon, (2) Zool. xiv. pt. 2, 1911, 

 p. 191 sqq. 



t Iv. Doii2las Laurie, Herdraan's Rep. Ceylon Pearl Oyster Pish. (Royal Soc, 

 Loudon) V. i906, p. 349 sqq. 



