Prof. T. Rupert Jones — Fossil B waived Entomostraca. 107 



not accompanied by a gaping of the valves, as in Asterope and 

 other Cypridiuads. 



The characteristic feature of Cypridea is sometimes expressed 

 only by a very small notch under a diminutive beak, or by even 

 a slight indenture below and behind a thickening of the antero- 

 ventral angle, as in Fitton's specimen of C. Valde^isis, fig. 1, pi. 21, 

 Trans. Geol. Soc, 2nd ser. vol. iv. Sometimes it is obsolete, or 

 traceable only by a curvature of the inside edge. Sowerby's G. 

 tubercidata and C. granulosa do not exhibit any notch in his figures, 

 nor in our examined specimens. C. granulosa is also described by 

 Sowerby as wanting the anterior " lobe " seen in C. Valdensis. His 

 fig. 3a, of C. spinigera does show a linear trace of the notch, de- 

 fining a marginal lobe. In a form closely related to G. spinigera, 

 shown in the accompanying Plate (Figs. 9 and 10), we also see such 

 an antero- ventral indentation. In Figs. 4, 5, 6, and 7 of our Plate, 

 we have several conditions of a form related to Sowerby's G. granu- 

 losa, but with strong indications of notch and beak. 



It is, of course, highly desirable to make as few generic divisions 

 as possible of these thick-shelled, oblong or ovate-oblong Ostracoda 

 of the Wealden and Purbeck beds. If "notched" in any degree, 

 they may be referred to Cypridea ; but it is often difficult to deter- 

 mine whether or no the notch be obsolete, reduced to a minimum, or 

 altogether absent. Those without any trace of the notch, such as 

 Sowerby's G. tubercidata, can be referred only to Gythere at present, 

 unless, on the ground of their having otherwise a general re- 

 semblance, we venture to group them as Gypridece with an obsolete 

 notch. 



C. — There is, however, another and distinct kind of Ostracodous 

 valve associated with the foregoing in the Shotover hand-specimen 

 of Ironstone, and in the black Cyrena-shale of Hanover. These 

 latter I wrongly correlated in the " Monogr. Foss. Estheriae" (Pal. 

 Soc), 1862, Appendix, pp. 122 and 123, with Cypridea Valdensis 

 (Sow.) and C. ohlonga (Pioemer), both of which are notched and 

 beaked. After further consideration I am satisfied that figs. 30-34 

 in pi. 5 of the Appendix to the " Monogr. Foss. Esth." are closely 

 related in form and structure to the recent Candona Candida (Muller) 

 and its allies ; except, perhaps, that fig. 31 may be a Danoinella. 

 They possess neither the notch nor the thick shell of the other 

 Purbeck- Wealden forms ( Cypridea Valdensis, etc.) ; but resemble 

 very much some common Cyprides and Candonce, and the less-known 

 Danoinella, in their thin, shining, oblong, and apparently hingeless 

 valves. Fig. 30, indeed, somewhat compressed, and drawn with the 

 posterior end upwards, is probably the same as one found at Shot- 

 over, and may be regarded as a Candona ; see further on. Fig. 31 

 is extremely like Darwinella Stevensoni, Brady and Eobertson,' in 

 outline. Figs. 32-34 may be three different Cyprides or Candonce, 

 as far as the valves indicate special features.^ The importance of 



1 Monogr. Post-Tertiary Entom. 1874, p. 141, pi. 2, fig. 13. 



^ "We may remark that fig. 25, on the same plate, representing Candona Kotahensis, 

 from the Jui-assic beds of India, has almost exactly the outline of the recent 

 Candona lactea. 



