394 DE. G. S. BEADY ON THE OSTEACODA 



ovate, with wide projecting extremities. The valves have a rugose, tuberculated rib 

 running diagonally across from before backward, and are otherwise irregularly sculptured 

 in a rugose manner. Length -^g inch (0-98 millim.). 



One specimen in the Trophon-hed (Sables superieurs), one in the Panoj)(ea-hed 

 (Sables inferieurs), and one or two in the Isocardmm-hed (Sables moyens). 



In general aspect these specimens are rather like Cythere costata, Brady, but differ 

 in their style of sculpture and in the fact of the postero-inferior angle being rounded 

 off instead of being produced as in C. costata, with a dentate projection. 



Cythere subcokonata, Speyer. (Plate LXVII. figs. 4 «-4 d.) 



Cythere subcoronata, Speyer, loc. cit. p. 38^ pi. iv. fig. 9 (1863). 



? Cythere latidetitata, Bornemann, " Die mikroscop. Fauna des Septarienttones von Hcrmsdorf," 



Zeitschr. d. deutsch. geol. Ges. 1855, p. 366, pi. xxi. fig. 6. 

 ? Cythere horrescens, Jones, Tertiary Entom. p. 38, pi. v. figs. 9, 17a, 176 (not Cythere horrescens, 



Bosquet; nor Cythereis subcoronata, Brady, Trans. Zool. Soc. Lond. vol. v. p. 384', 1865). 



Carapace, as seen from the side, oblong, subovate, somewhat higher in front than 

 behind ; height equal to rather more than half the length ; extremities rounded, the 

 anterior armed below the middle with a series of strong, blunt, projecting spines, the 

 posterior with a few broader and less developed somewhat triangular teeth ; dorsal 

 margin sloping in an almost straight line, but tuberculated and terminating behind in a 

 very large and much elevated blunt spine or tubercle ; ventral margin convex. Outline 

 as seen from above subovate or almost hastate, irregularly jagged or laciniate, widest 

 towards the hinder extremity, the width being equal to the height. End view sub- 

 triangular. The surface of the valves is beset with irregularly scattered, large, rounded 

 tubercles, and along the ventral and dorsal margins with a row of blunt tooth-like 

 processes. Length -^ inch (0-98 millim.). 



Though Professor Jones's figures differ, more especially in the sharply spinous 

 character of the armature, from the Antwerp specimens, I think it extremely likely 

 that they really apply to mere varieties (perhaps sexual) or to stages of growth of the 

 present species. And I also strongly suspect that the species itself, as illustrated in 

 PI. LXVII. figs. 2 a-d of this Memoir, may only be the immature form of Cythere 

 mucronata, a strikingly developed specimen of which is shown in figs. 3 a-d of the 

 same Plate. If the two series of figures be carefully compared, it will be seen that 

 they diflFer scarcely at all, except in the degree of development of the various parts ; 

 and though I hesitate, in the absence of a series of specimens exhibiting the inter- 

 mediate stages of growth, to unite them under one specific name, I really entertain 

 very little doubt as to the propriety of doing so. 



C. subcoronata has been found sparingly in the Pectunculus-hed (Sables inferieurs) 

 and in the zone a Isocardium (Sables moyens). 



