tx are the eyes separated by a distinct interspace. The structure of 

 the eyes is rather simple, and they contain only a very limited number of visual 

 elements, corresponding to an equal number of more or less refracting corneal 

 lenses of the integument. In the adult male, they are generally more fully devel- 

 oped than in the females. 



The superior antennae are rather small, each consisting of a 3-articulate 

 peduncle, and 2 diminutive flagella, the inner of which is sometimes quite obso- 

 lete. The outer flagellum is tipped with one or 2 slender sensory filaments, and 

 in the adult male, an additional bundle of such filaments is generally attached to 

 the base of this flagellum. 



The inferior antennas are in the female, as a rule, very small and rudi- 

 mentary, whereas in the adult male they are greatly developed, generally at- 

 taining the length of the whole body. In structure, they resemble those in the 

 male Phyllocarida and Amphipoda, each consisting of an angularly bent peduncle, 

 the outer part of which is densely clothed with sensory fiaments, and, together 

 with the slender, niultiarticulate flagellum, extends straight backwards. They are 

 generally borne closely applied to the sides of the body, and thus easily escape 

 observation; but they admit of being moved from this position, and are probably 

 subservient to copulation. This could be directly proved in the species of the genus 

 Lainprops, where they are used as true prehensile organs, to obtain a hold of the 

 female during copulation. 



The oral aperture is bounded in front by a generally small and simple, 

 rounded anterior lip (which is more strongly developed only in the genus Cam- 

 pylaspis), and behind by a lamellar, bilobed posterior lip. 



The mandibles are strongly incrusted, and are in no case provided with 

 palps. They are articulated to the inner side of the carapace just at the points 

 where the diverging fissures encompassing the frontal lobe, terminate, and they are 

 extended obliquely in front. The masticatory part is divided into 2 diverging 

 rami, the anterior representing the cutting part, the posterior the molar expans- 

 ion. The latter, in the greater number of forms, is rather thick, cylindric, and 

 exhibits at the end a finely fluted triturating surface. The former has generally 

 a dense series of curved spines immediately behind the cutting edge. 



The anterior maxilla? exhibit the 2 usual incurved lobes, the masticatory 

 and basal, the former being much the stronger, and armed at the obliquely 

 truncated tip with short spines. The palp is peculiarly modified, and turned 

 straight backwards, terminating in one or 2 band-like bristles, which project 

 into the branchial cavity. It is wanting in 2 of the known genera, viz., Par- 

 lamprops and Plati/aspis. 



