218 



POST-TERTIARY ENTOMOSTRACA. 



■• female scarcely longer than the succeeding joints ; secondary branch in the male robust, 



subchelate ; terminal joint slender, curved upwards ; in the female simple, triarticulate, 

 last joint setiform. First jaw consisting of a broad, subquadrate, or crescentic lamina 

 densely clothed on its distal margin with long bristles ; second jaw swollen at the base, 

 narrowed at the apex, where it bears six plumose set^, basal portion setose along its 

 convex margin ; third jaw narrow, elongated, setose along the inner margin. Post- 

 abdominal laminae short and broad, subtruncate at the apex. 



In external appearance this genus is chiefly distinguished from others of its family by 

 the cylindrical form of the shell and the absence of a projecting beak. 



AsTEROPE TERES {Norman) . Plate II, figs. 33, 34, 



1861. Cypkidina teres, Norman. Ann. Mag. N. H., vol. viii, pi. xiv, fig. 10. 

 1868. Cylindiioleberis teres, Brady. Monog. Rec. Brit. Ostrac, p. 465, pi. 



xxxiii, figs. 6 — 9, and pi. xli, fig. 2. 

 18/1. AsTEROPE — Brady. Proc. Zoo). Soc. Lond., 1871, p. 295. 



Shell, seen laterally, almost elliptical, wider behind than in front, the greatest height 

 behind the middle and equal to at least two thirds of the length. Anterior extremity 

 slightly narrowed and somewhat flattened, with a wide, but shallow, notch below the 

 middle ; obtusely subangular below, rounded off above ; posterior extremity broad, boldly 

 and evenly rounded ; superior margin evenly and well arched ; inferior almost straight 

 for the first half of its course, but curved posteriorly. Seen from above, oblong-ovate, 

 anterior extremity narrowly, posterior rather broadly, rounded ; greatest width situated 

 near the middle, and equal to nearly half the length. Surface of the shell smooth, dense 

 and calcareous in structure. 



Length, ygth of an inch. 



It is extremely probable that this is only the female of the much more commonly seen 

 Asterope Maria, which differs, however, very considerably in external appearance, being 

 much longer and more compressed, more delicate in shell structure and variously coloured. 

 The anatomy of the two animals is, however, essentially the same, and the points of 

 difference are such as might be expected to accompany difference of sex, though, doubt- 

 less, very strongly developed in this instance. The male, being provided with swimming 

 filaments, is usually taken near the surface of the water, while the female is never met 

 with except in the dredge. Under these circumstances we need scarcely expect to find 

 the male in the fossil state. 



Distribution. Recent. — North Sea, West Coasts of Scotland and Ireland, Scilly, and 

 Channel Islands. 



Fossil. — Scotland : Jordan Hill. 



