46 THE VOYAGE OF H.M.S. CHALLENGER. 



Samboangan. Miers has called attention ^ to the fact that in the single female with the 

 large raptorial limbs which he has been able to examine, the spines arming the 

 inner margin of the dactylus, instead of being strong and elongated as in the males, are 

 very short, and towards the base are reduced to little more than small serrations or teeth. 

 The fact that there is the same difference between the raptorial claws of the males and 

 that of the female in the Challenger series would seem to indicate that this difference 

 between the sexes is constant. The raptorial claw of a large male is shown in PI. X. 

 fig. 1, and that of the female in fig. 2. This difference is the more remarkable as 

 secondary structural differences between the sexes are extremely rare among the 

 Stomatopods. The male of Pseudosquilla ciliata is said to be more brilliantly coloured 

 than the female, and the female Lysiosquilla excavatrix is larger and darker coloured than 

 the male, but there are no structural differences except the modification of the endopodite 

 of the first abdominal appendage which is found in all male Stomatopods. The sterna of 

 the free thoracic somites of the female Lysiosquilla maculata are much thicker and stouter 

 than those of the male, and the median ventral carinse larger. 



The first abdominal appendage of the male is shown in PI. X. fig. 6. The endo- 

 podite is elongated and shorter than the exopodite ex, and its terminal joint B is triangular, 

 wider than long, with the inner lobe h very much smaller than the outer lobe a, from 

 which it is separated by a suture. The inner lobe is nearly circular, with a deep notch 

 on its distal edge ; the appendix interna is long and prominent ; the movable Hmb f of 

 the forceps is acute and long, while the immovable limb is very small and scarcely visible. 



Ontogeny. — The largest Erichthus larva in the Challenger collection, a Lysio- 

 erichthus, is the same as the one shown in Claus's figure 16, and probably identical with 

 Erichthus duvaucellei, Guer. It is shown in PI. X. fig. 7. It is very widely distri- 

 buted, and the collection contains numerous specimens from various localities in the 

 West Pacific. Specimens were taken in the tow-net between Api and Cape York, 

 between Admiralty Island and the coast of Japan, in the Straits of Mindoro, and at 

 other points, while Claus's specimens were obtained in the Indian Ocean, and Guerin's in 

 the Gulf of Bengal. 



Its resemblance to the larva from which I have reared Lysiosquilla excavatrix 

 shows that it is a Lysiosquilla, and, like Lysiosquilla maculata, it is somewhat excep- 

 tional, since the inner spine of the uropod is longer than the outer, while most of the 

 adult Lysiosquillse, and most of the Lysioerichthus larvae, have the outer spine longest. 

 The raptorial claw is long and slender, and it exhibits traces of eight marginal spines, 

 whde the adult female Lysiosquilla maculata has seven or eight and the adult male 

 nine. 



The abdomen of the oldest larva is marked by the transverse dark bands which are 

 so characteristic of the adult Lysiosquilla maculata, and I cannot doubt that this 



1 Miers, On the Squillidse, p. 6. 



