DESCRIPTION OF GENERA AND SPECIES. 



Order PODOPHTHALMIA. 



Suborder SCHIZOPODA. 



Family 1. Lophogastrid^. 



This family, formerly represented only by a solitary genus, Lophogaster, has acquired 

 a very considerable augmentation by the material collected during the Challenger Expedi- 

 tion, three interesting new genera having been added, one of which (Gnathophaitsia) is 

 represented by no less than nine different species. 



I have placed this family at the head of the suborder, since it would seem to comprise 

 the most highly organised forms of Schizopoda. This may easily be shown by comparing 

 the structure and development of the several organs with the corresponding ones in other 

 Schizopods, and especially by examining the branchial apparatus, the highly differenti- 

 ated structure of which gives full evidence of the high rank occupied by these forms. 

 The fact that by far the largest and most powerfully developed species are to be found 

 in the present family, would seem also to support such a view. 



The late Professor M. Sars, my father, had already stated that the genus Lopliogaster, 

 which constitutes the type of this famil}^, exhibits in several respects a striking affinity to 

 some of the lower Macrura (Caridea). Exclusive of the strong development of the gills, 

 may also be noted the structure of the integuments, which are more or less calcified or 

 indurated, and in some cases even exhibit a distinctly perceptible sculpture, not to be 

 found in any other Schizopods ; moreover, the comparatively powerful structure of the 

 legs renders those organs apparently more efficient for the office of true pereiopoda, than 

 is the case with the other known forms of this suborder. From the Macrura they may, 

 however, be easUy distinguished, not only by the incubatory pouch of the females, but 

 also by the uniformly developed biramous legs, none of which exhibit any trace of a 

 cheliform or even subcheliform structure. 



A sjTiopsis of the four genera comprised in this family is given below : — 



Carapace 



covering only the 

 anterior division of 

 the body. Rostrum 



short, forming together 

 •with the supra- 

 orbital spines a broad 

 tridentate frontal plate. 

 Antennal scale 



broad, cordifomi, with 

 the inner edge 



setose, . 



narrow, 

 without 

 set*, 



flexuous, 

 marginal 



Lophogaster. 



Ceratolepis. 



more or less produced, spear-shaped, denticulate, Gnathophausia. 

 covering whole of tlie anterior division of the body and part of posterior, . Chalaraspis. 



