458 Jones and Sherhorn — Tertiary Entomostraca. 



must relegate C. Zondiniensis, Jones, ' Monogr. Tert. Entom.' p. 54, 

 pi. Y. figs. 20 [reproduced here, PI. XI. Fig. 19] and 22, besides^ 

 " C. compressa, var. 2," Fig. 19 of the same Plate. 



Group II. CytJierella Muensteri (Roemer). These carapaces have 

 their greatest convexity near the middle or towards the hinder part 

 of the valves. One of our specimens from Bracklesham belongs to 

 this group ; but we know of none exactly like it, in its symmetrical, 

 broad, and oblong outline, with nearly equally rounded ends, 

 median convexity toward the ventral edge, and broadly ovate edge- 

 view. . We call it C. Boemeri. Another is near Roemer's original 

 figure, 'Neues Jahrbuch, fiir Min. etc' 1838, p. 516, pi. vi. fig. 13, 

 in shape, though not so strongly punctate. In the ' Monogr. Tert. 

 Entom.,' p. 56, pi. v. fig. 13, is a smooth variety ; but fig. 12 is even 

 more strongly pitted than is Eoemer's fig. 13, and was termed var. 

 rectipunctata in the Geol. Mag., 1870, p. 157. Some allied forms, 

 smooth and having the convexity more definitely in the hinder third 

 of the valves, are remarkably ovate in outline, and lanceolate in 

 edge-view. These may be regarded as belonging to a new species, 

 to be called C. Beussii, after the eminent micrologist of Prague and 

 "Vienna. In the ' Monogi". Tert. Entom.,' p. 54, pi. v. figs. 21 [re- 

 produced in our PI. XI. Fig. 17] and 23 are also smooth, and belong tO' 

 this group : but they are obovate in outline, like Bornemann's 0. 

 fabacea, ' Zeitschr. Deutsch. geol. Ges.,' vol. vii. 1855, p. 355, pi. xx. 

 fig. 2, to which they must be referred, as in Geol. Mag. 1870, 

 p. 157. Another of our Tertiary Cytherellcs is ovate-oblong, lanceo- 

 late in edge view, with acute-ovate end-view. This also we believe 

 to be new, and name it C. Dixoni, in memory of one of the most 

 enthusiastic workers on the geology and fossils of Bracklesham, 

 whence all but one of the Cytherellce described as new in this paper 

 have been obtained. 



A very small Cytlierella, smooth, snbovate, and with lanceolate 

 edge-view, belongs apparently to Gi'oup II. It was found by Mx*. 

 Clement Eeid in the Weybouru Crag of East Eunton. 



Gkoup III. The type is CytJierella Beyrichi (Eeuss). 



Cytherina Beyrichi, Reuss, Zeitschr. Deutsch. geol. Ges., vol. iii. 1851, p. 89, pL y'n^ 



fig. 65. 

 Cytlierella Beyrichi, Bornemann. Ibid. vii. 1855, p. 354, pi. xx. fig. 1. 



,, compressa, var. 1, Jones. Mojiogr. Tert. Entom. 1856, p. 55, pi. v. fig. 18. 



[Reproduced here, PI. XI. Fig. 18.] 

 ,, Beyrichi, Speyer, Ostrac. Cassell. Tertiar., 1863, p. 54, pi. i. fig. 1. 

 ,, Beijrichi, Brady, Trans. Zool. Soc, vol. v. 1866, p. 362, pi. ivii. fig. 3. 

 ,, „ Jones, Geol. Mag. 1870, Vol. VII. p. 157. 



In this group the carapaces vary from round-ended oblong to ovate- 

 oblong, with a partial flattening of the anterior portion, giving a. 

 compressed wedge-shaped edge-view. In most cases the posterior 

 end is full and truncate, herein also difi^ering from the members of 

 Group II. Generally the surface is pitted, but we have a smooth 

 example of this form. The last may be termed C. Beyrichi, var. 

 Icevis ; but we consider that the others do not offer differences sufficient 

 to separate them from the type as named varieties. 



