CRUSTACEA. 151 



gin, and from them on each side an obscure impressed hne 

 extends upwards and inwards to about the first third of the 

 glabella (perhaps indicating the eye-line) ; glabella very con- 

 vex, semiclliptical, obtusely rounded in front, surrounded by 

 a strong defining sulcus ; two segmental furrows on each side, 

 the first very strong, curving, from about the middle of the 

 sides of the glabella, inwards and backw^ards into the neck- 

 furrow, so as to include a large tumid ovate lobe on each side ; 

 a little above this, the very short and faintly marked anterior 

 segmental furrow curves in the same direction ; surface granu- 

 lated. (Type of the genus Harpes ? megalops, M^Coy, Syn. 

 Sil. Fos. Irel. t. 4. f. 5.) 



The head alone of this genus is known, which differs from 

 Harpes (Gold.) in its small size, narrow unpunctured rim, ab- 

 sence of the ocular tubercle on the anterior part of the cheeks, 

 great size and basal position of the eyes, &c. 



(Fam. Lymnadiadce.) 



Ceratiocaris (M^Coy), n. g. 



Etym. Kepdrtov, siliqua, and KapU, squilla. 



Gen. Char. Carapace bivalve, the dorsal line simply angulated 

 (? undivided), with a slight furrow beneath it on each side; 

 sides semielliptical, much elongated from before backwards, 



evenly convex, ventral margin gently 



convex, posterior end abruptly trun- J/ 

 cated obliquely ; on each side near the # 



anterior end considerably below the 



hinge-line is an ocular (?) spot, some- Ceratiocaris. 



times raised and distinct, in some spe- «• The ocular spot, 

 cies flat ; surface marked with fine, imbricated striae, obliquely 

 longitudinal. 



In their pod-like form some of the species resemble such shells 

 as Solenocurtus and Solenimya, except in the abrupt truncation 

 of the posterior end ; others resemble the Crustacean genus 

 Dithyrocaris, with which I think their affinity lies, though they 

 differ in form and want the peculiar ridges of that group. I 

 conceive they were phyllopodous Crustaceans allied to Lymnadia ; 

 the peculiar texture and kind of lineation of the surface resemble 

 what we find in Crustacea allied to Apus rather than in Mol- 

 lusca ; the general pod-like form, large size, and posterior trun- 

 cation separate them from any of the large species of Cythere 

 or Cypridinia, and the two ocular spots separate them from all 

 others. 1 suspect from some of the specimens that the two sides 

 meet along the dorsal line at an angle of 45°, with probably little 



