ULRICHIA. 23 



third coalesce below, wbile the central lobe seems sometimes more defined. 

 Posterior lobe sometimes bifid. 



Size. — Length 1*5 mm. 



Locality. — Numerous specimens from the Ostracod Bed, Laticosta Cave, Baggy 

 (where it seems to occur frequently) are in my Collection. 



Remarhs. — This species seems variable, but the variation is partly to be 

 accounted for by the immense squeezing 'and twisting "which the beds have under- 

 gone, as seen by the shapes assumed by larger fossils.. Hence it is hard to arrive 

 at the true form of the species. The specimens numbered 22 and 23 are examples 

 of shortened aspects it assumes under distortion, and at first sight appear to belong 

 to different genera, but on examination prove to be the present species. On the 

 other hand elongate valves with faint ridges, represented by figs. 19 and 20, occur 

 frequently ; it seemed at first that these must be distinct, but on tracing out the 

 diflferences seen in numerous specimens it becomes evident that they are simply due 

 to fossilisation, and that they cannot be separated from the rest even as a variety. 



Affinities. — Kloedenia notata, sp., Hall,^ seems not unlike, and possibly under 

 varying pressures would present similar forms. 



7. Genus — Ulrichia, Jones, 1890. 

 1. Uleiohia iNTEESEETA, n. sp. Plate III, fig. 24. 



Description. — Yalve long, semi-oval. Dorsal border straight, almost as long- 

 as the valve. Yentral border elliptic. Ends rather strongly and evenly rounded ; 

 with thickened margins rising up from the ventral border. Surface bearing two 

 large, prominent, obliquely oval, median well-defined lobes, not united below. 



Size. — Length '8 mm. 



Localities. — There is one specimen in my Collection from the Ostracod bed at 

 Baggy. 



BemarJiS. — This fossil is regarded by Rupert Jones as an Ulrichia. It appears, 

 however, to mark a passage from that genus to Bollia ; for, while the lobes are 

 distinctly defined below, there is a decided thickening of the lower portion of the 

 valve. This passage between the two genera is continued by Bollia bilobata, Jones, ^ 

 which has equally large lobes, united by a low swelling. The latter is also distin- 

 guished by being more oblong. 



1 1890, Jones, ' Quart. Journ. Geol. Soc.,' vol. xlvi, p. 13, pi. iv, figs. 22, 23, and var., fig. 24. 



2 1890, Jones, ' Quart. Journ. Geol. Soc.,' vol. xlvi, p. 540, pi. xx, fig. 12. 



