iitudies on marine Ostracods 269 



C. (Vargula) megalops G. 0. Sars. 



Cypridina megalofs, (J. f). SaKS, 1872, p. 278. 



G. S. Brady and A. M. Nokmax, 1896, p. 649; pi. LIV, figs. 5, 6. 

 (;. W. MULLER, 1912, p. 15. 



Description: —Female!: ■ — 



Length, 3 ram. Length : height, about 1,43 : 1; length : breadth, about 1,85 : 1. 

 Seen from the side (fig. I ) it is broadly egg-shaped with the greatest height situated 

 rather considerably behind the middle and the posterior part rather strikingly larger than the 

 anterior one. The dorsal margin is rather boldly arched, its arcuation being somewhat more 

 pronounced posteriorly than it is anteriorly, and, like the ventral margin, which is uniformly 

 and somewhat more slightly arched, joining the anterior and posterior margins without decided 

 corners. The rostrum is well rounded anteriorly or has a broadly rounded and rather weakly 

 developed anterior corner; its ventral corner is rather well pointed. The rostral incisur is deep 

 and narrow. The posterior part of the shell is broadly rounded and has a weakly developed and 

 broadly rounded posterior corner at about half the height of the shell. Seen from below 

 (fig. 2) the shell is oviform with its sides evenly arched and its greatest breadth situated somewhat 

 behind the middle; the anterior end is somewhat more narrowly rounded than the posterior one. 

 The surface of the shell is quite smooth except in the neighbourhood of the anterior 

 margin of the shell, where it appears to have small, rounded cavities. The bristles of the surface 

 seem practically to be entirely lacking. The pores of the surface are, on the contrary, very 

 numerous and rather large and striking. Seen from inside (fig. 3): Medial bristles: 

 On the rostrum there is a fairly close row of rather short and in most cases bifurcated bristles 

 ruiming obliquely upwards and forwards. The place on which the ventral ones of these bristles 

 are fixed does not form a verruciform swelling. Apart from these bristles there are only a few 

 found on the rostrum. Apart from the two bristles situated close to each other near the inner 

 margin of the incisur there is generally only a single bristle inside the incisur; this bristle is 

 short and is situated somewhat dorsally of the two just mentioned. Along the anterior part 

 of the list there is a moderate number of bristles, mostly bifurcated, situated most closely 

 just behind the rostral incisur and becoming more and more sparse posteriorly, but observable, 

 however, along the whole ventral side of the shell. All the medial bristles are bare or almost 

 bare. The list within the posterior margin of the shell is somewhat wider than it is anteriorly and 

 has no other appendages except a comparatively few short, simple bristles, which are difficult 

 to distinguish. On the part of the shell between the list and the margin there seems as a rule to be 

 practically no bristles. The selvage is wide, extending rather considerably beyond the edge of 

 the shell both along the anterior and posterior margins of the rostral incisur — the incisur is 

 quite filled with it — as well as along the anterior edge of the rostrum. Along the whole ventral 

 side of the shell the selvage also is comparatively wide — although considerably narrower than 

 it is anteriorly — extending somewhat beyond the edge of the shell. It is finely and fairly 

 uniformly cross-striated. The shell is rather strongly calciferous, but thin and fragile. 



