392 DE. G. S. BEADY ON THE OSTEACODA 



above is elongated, subhexagonal, sides nearly parallel but deeply sinuated in the 

 middle ; sides gradually tapering to the anterior extremity, which is broad and truncate ; 

 posterior extremity very wide, with a wide central mucronate projection. End view 

 broadly ovate, height and width nearly equal, outline irregularly waved. The shell- 

 surface is sculptui'ed with large pits, which are arranged in obscurely radiating, some- 

 what flexuous lines round a central tubercle ; parallel to and just within the inferior 

 margin is a distinct elevated ridge. Length -^ inch (0'75 millim.). 



This species may perhaps be identical with that called by Egger " Cythere corrugata, 

 Reuss ;" but if so Dr. Egger's identification must be wrong, as Eeuss's figures certainly 

 do not apply to the present species. It was found in the Trophon-antiquum bed (Sables 

 superieurs). 



Cytheee mackopoea, Bosquet. (Plate LXVII. figs. 1 a-1 d, and Plate LXVI. 

 figs. 6 a-6 d). 



Cythere macropora, Bosquet, Entom. fossil, terr. Tertiair. France, p. 97, pi. v. fig. 2 ; Jones, Tert. 



Entom. England, p. 35, pi. iii. figs. 9a-9e ; Brady, Crosskey, and Robertson, Monog. Post-tert. 



Entom. Scotland, &c., p. 159, pi. xiv. figs. 1-3. 

 "^Cythere logani, Brady & Crosskey, Geological Magazine, vol. viii. (1871), pi. ii. figs. 8, 9. 

 Cythere hornesi, Speyer, op. cit. p. 32, pi. iii. fig. 7, and pi. iv. fig. 1. 



Carapace, as seen from the side, oblong, quadrangular, highest near the front, height 

 equal to fully one half the length ; anterior extremity broad and well rounded, posterior 

 rounded but narrower ; dorsal and ventral margins nearly straight, the former sloping 

 rather steeply backwards. The outline as seen from above is oblong and very irregular, 

 the margins much jagged and waved; extremities produced, very broad and truncate, 

 width about equal to the height. The shell-surface is beautifully sculptured with large 

 angular pittings, which are arranged somewhat concentrically round a large rounded 

 central tubercle ; the pitted portion of the valve ends at some distance from the hinder 

 extremity, in an irregular, curved, abrupt declivity, and is connected with the anterior 

 margin by a series of about six short radiating ribs. The anterior margin is fringed 

 below the middle with a series of 12-16 short blunt teeth ; the posterior margin also 

 bears about six or eight distant irregular teeth of similar character. The ventral 

 aspect of the shell shows a very broad, prominent central ridge formed by the swollen 

 margins of the valves, and on each side a laterally produced expansion ornamented by two 

 longitudinal rows of deep subangular excavations. Length 2^ inch (1-05 millim.). 



C. macropora occurs in both beds of " Sables moyens " (abundantly in that of the 

 zone a Bryozoaires), and also very abundantly in the Panopcea-heA ("Sables infe- 

 rieurs "). It is certainly one of the most distinctly marked and most beautiful of fossil 

 Entomostraca. A recent Australian species {Cythere lactea) described by the present 

 writer in 1865 (Trans. Zool. Soc. Lond. vol. v.) comes near to it in character, but is quite 

 sufficiently distinct. The form represented in PL LXVI. of this Memoir seems to belong 

 to the young, and is probably identical v,ith C. hornesi, Speyer. 



