438 PROCEEDINGS OF THE NATIONAL MUSEUM. vol. xsxv. 



with a single strongly curved claw. These organs are articulated 

 with the face at its extreme lateral margins, so that on opening they 

 expose the entire width of the face. 



There is but a single pair of rudimentary swimming legs, which 

 are short, narrow, and bluntly rounded at their tips. 



Total length, 3 mm. Length of head, 0.8 mm. ; width the same. 

 Length of genital portion, 2 mm. Width, 1.1 mm. Length of egg 

 strings, 3 mm. 



Color. — That of transparent cartilage, with the exception of the 

 coiled oviducts in the genital portion, which are white and opaque. 

 The small spines which cover the genital portion break the light and 

 give this part of the body a grayish appearance. The eggs are snow 

 white when first laid, becoming yellow as they ripen and afterwards 

 a beautiful rose red or pink. There is so much of this pigment in the 

 matured nauplius that the entire egg strings assume a deep rose 

 color. 



Male. — A pigmy attached to the abdomen of the female; the first 

 thorax segment united with the head to form a cephalothorax much 

 larger than the rest of the body, and covered with a three-lobed 

 carapace whose lateral margins are broadly rounded and project 

 some distance back of the central portion. Free thorax not dis- 

 tinctly segmented ; no abdomen ; anal laminae in the form of long- 

 conical processes, divided at the ends for half their length. Second 

 antennae and mouth parts similar to those of the female ; maxillipeds 

 relatively as large and opening similarly; rudimentary legs entirely 

 lacking. 



Total length, 0.43 mm. Width of cephalothorax, 0.2 mm. 



Color. — A uniform light yellow. 



Nauplius.— Body broadly elliptical, with an evenly curved out- 

 line unbroken either at the anterior or posterior ends. The usual 

 three pairs of appendages, all of which are relatively large for the 

 size of the body. Eyes three in number and arranged in the form 

 of a triangle close to the anterior margin, the apex of the triangle 

 pointing forward. Balancers short, stout, and close together on 

 either side of the mid-line; each is conical in form and curves out- 

 ward and backward away from its fellow. 



Total length of body, 0.15 mm. Width of same, 0.12 mm. 



Color. — A deep rose red. rilling the entire anterior four-fifths of 

 the body. Not only (he yolk, which is the portion usually taking the 

 pigment, but the entire anterior half of the body, which in most 

 nauplii is clear and transparent and without pigment, is here covered 

 with a heavy rose wash, nearly concealing the muscles and eyes. 



(diceraus, dig, double, and Kepaog, horned.) 



This new genus is sufficiently* distinguished from Chondr acanthus 

 by (he fact that there is only one free thorax segment and a single 



