228 THE S('HIZ(^P()DA. 



In more than half-grown, l:)ut innnature, specimens the leaflet of first joint is 

 more rapidly and evenly narrowed, not truncate, but with the terminal portion 

 produced r.uich upwards and considerably outwards (fig. 2f), the inner margin 

 being very convex towards the acute tip and the outer considerably concave ; 

 the tooth at the end of second joint is much longer and the acuminate part of 

 the outer distal protuberance of the first joint consideralsly longer than in the 

 adults. — The antennal squama does not reach the end of second antennular 

 joint (fig. 2a) ; its terminal margin is transverse or a little oblique, with the outer 

 denticle very distinct; the two distal joints of the stalk of the endopod are 

 similar in both sexes. 



Sixth abdominal segment with a distinct dorsal spiniform tooth at the end. 



The copulatory organs (figs. 2h-2i) afford some specific characters. The 

 distal half of the inner lobe (H.) is subtriangular, rounded at the end; the distal 

 two thirds of the free outer margin of tlais lobe is serrate, and its proximal half 

 shows two obtuse protuberances between wluch the margin is rather concave. 

 The median lobe (Im.) is extremely short, cut off transversely, and from the 

 inner part of the terminal margin the somewhat long lateral process (p\) pro- 

 jects; this process is bent a little outwards at the acute end. 



Length of the largest male 11.5 mm., of the largest female 14 mm. One of 

 Ortmann's males from the Gulf of Panama is 13.2 nun. long. 



Very young Specimens^ (Plate 7, figs, la-lb). — The specimen figured 

 measures 7 mm. ; other somewhat smaller specimens are at hand. — The frontal 

 plate is at the base as broad as the carapace; it is much produced, longitudinally 

 concave, its lateral margins are sinuate, being proximally convex and distally 

 concave, and the plate is distally truncate, even flatly emarginate, each angle 

 being produced in an acute tooth; at the end the plate is about one third as 

 broad as at the base. In the largest specimen the carapace has scarcely any 

 angle on the lateral margin somewhat before the hind margin, Init in the other 

 specimens an angle or generally a small denticle is distinct. The eyes are 

 extremely large. The leaflet of first antennular joint in the largest specimen 

 directed upwards and somewhat backwards, somewhat excavated above beyond 

 the base, a little longer than broad, nearly oblong-triangular, with the inner 

 margin straight, the outer somewhat convex, and the distal part produced in 

 an acute tip bent upwards and somewhat forwards but not outwards; in some- 

 what smaller specimens the leaflet is proportionately smaller and less developed ; 

 the process from the outer distal angle of first joint very long. Second and 

 third antennular joints in the main as in the subadult. 



' The larvae of this species are dealt with, p. 28S-200. 



