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



its posterior edge, between the submedians. There is one small secondary spinule 

 internal to the base of the lateral marginal spine, another internal to the base of the 

 intermediate, and a third midway between this and the submedian. In figs. 7 and 8 

 as in the young Gonodactylus the outer edge of the proximal joint of the exopodite of 

 the uropod is fringed by nine marginal spines, the terminal one longest, and the outer 

 spine of the basal prolongation is much longer than the inner, but not as long as it is in 

 Pseuderichthxis. A comparison of the telson of the young Gonodactylus with that of 

 the other larvae which are figured in this paper, will show that none of them except 

 those now under discussion exhibit this resemblance. The Gonerichthus larvae which 

 are here figured are all of them well advanced, and are furnished with large compound 

 gills on their abdominal feet ; this, together with the perfect development of their 

 uropods, shows that they are nearly mature, and about ready to moult into the adult 

 form, and as none of them exhibit any traces of marginal spines on the dactylus of the 

 elongated slender raptorial claw, we may feel confident that the adults belong to a genus 

 in which the dactylus is unarmed. It is not probable that a larval type which is so 

 common pertains to an unknown adult genus ; the larvae are not P'rotosquillse, as the 

 sixth abdominal somite is well developed, and as they have no movable spinules on the 

 tips of the submedian spines of the telson they are not Pseudosquillee. The only 

 remaining genus is Gonodactylus, and their structural characteristics .all indicate that 

 they are the young of species in this genus. Claus, who has figured two of these larvae 

 in his figures 21 A. and 21 A', correctly refers them to Gonodactylus (p. 139) although he 

 also refers to this genus two larvae, figures 20 and 21 B. which are not Gonerichthi but 

 Lysioerichthi, as he indeed suspects may be the case with the second one, 21 B. 



The Gonerichthus larva may be distinguished from the Lysioerichthus by the 

 shallowness of its carapace, which is not at all infolded, and by the position of its postero- 

 lateral spines, which arise very close to the dorsal middle line. It is distinguished from 

 the P sender ichthus larva by the length of these spines, which are at least half as long as 

 the carapace, and also by the fact that the telson is wider than long, and longer than the 

 long outer spine of the uropod. 



