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



numerous marginal spines, there is little doubt that they are LysiosquiUa, pretty closely 

 related to the two which have been described. One of these, an Erichthus 14 mm. long, 

 from Bengal,^ he himself refers to the subgenus Coronis, and his Squillerichthus 

 triangularis (fig. 13) and possibly his Erichthus latreillei (fig. 18) are closely related 

 species. 



The Challenger collection contains many specimens of a number of species of this 

 larval type, some of them very broad and short, and others as narrow as a Gonodactylus 

 Erichthus, from which they are distinguished by the position of the postero-lateral spine 

 of the carapace, which is either on the ventral edge or nearer to it than to the dorsal 

 middle line, while the reverse is the case in the Gonodactylus larva, which also has its 

 hind body convex instead of flat. 



One of these Lysioerichthus larvae from a surface collection made by the Chal- 

 lenger at Papua, Japan, is shown in PI. XL figs. 10, 11, 12, and 13. It is y% of an 

 inch long on the middle line, with a minute dorsal spine, a rostrum which is nearly as 

 long as the carapace, small antero-laterals, and postero-laterals which spring from the 

 carapace close to its ventral edge, and reach backwards as far as the middle of the 

 sixth abdominal somite, while all the abdominal somites except the first are exposed 

 on the middle line. The raptorial claw (fig. 13) is flat, broad and oval, and its 

 dactylus shows under the cuticle traces of eight marginal spines. The hind body is 

 as wide as the carapace, and the telson (fig. 11) is much wider than long, with 

 its posterior border angulated and fringed with numerous small spinules between 

 the submedians, the distance between which is about half the greatest width of the 

 telson. There is a small spinule internal to the base of each lateral and each inter- 

 mediate marginal spine, and one small secondary spine between the intermediate and 

 snbmedian. 



Length of carapace including rostrum, 

 Length of exposed somites and telson. 



Total length on middle line, .... 

 Length of postero-lateral spines, .... 



The oval shape of the flattened carpus indicates that this larva is a Coronis. There 

 is a general resemblance between it and the one last described, but the raptorial 

 claw is less oval, and in a third closely related larva, collected between Sydney and 

 Wellington, the raptorial claw is still more elongated. This latter larva, which is shown 

 in PI. IX. figs. 6, 7, 8, 9, and 10, is so similar to the one shown in Claus's figure 20, 

 that they must represent related adults, and I am therefore compelled to dispute his 

 identification of his larva as a young Gonodactylus. 



It is remarkable for the great length of the rostrum and postero-lateral spines, the 



' Metamorphose der Squilliden, fig. 19. 



