64 Brady and Crosskey — Notes on Fossil Ostracoda. 



rounded off behind, inferior nearly straight ; seen from above sub- 

 hexagonal with subparallel sides ; anterior extremity obtusely pointed, 

 posterior broadly and obtusely mucronate, width equalling the height. 

 Shell robust, surface of the valves marked near the middle by a large 

 rounded tubercle, and a little within the inferior and posterior 

 borders by a sharply cut precipitous ridge (nearly straight below, 

 but forming a sigmoid curve behind), which marks off the sculptured 

 portion of the shell ; surface-sculpture consisting of irregularly 

 angulated pits, which are comparatively small and well defined 

 behind the central tubercle, but larger and vaguely impressed in 

 front. Length, l-40th of an inch, 



A fine and well-marked species, which we dedicate to Sir William 

 Logan, the excellent Director-General of the Geological Survey 

 of Canada. Cyihere macropora, Bosquet, seems to approach this 

 species somewhat closely, but is altogether less tumid, especially 

 behind the middle, and is distinctly dentate at the postero-inferior 

 angle. We noticed several examples of C. Logani in various stages 

 of growth among the Montreal specimens. 



Cyihere Dawsoni, Brady, Plate II., Figs 5, 6, 7. — We hei'e give 

 figures of a specimen which appears to belong to the male of C. 

 Dawsoni. The original figures in the "Annals and Magazine of 

 Natural History," for December, 1870, were imperfect, owing to the 

 accidental loss of the shell, which appears to have been that of a 

 female. 



Cyihere cuspidaia, nov. sp., Plate II., Figs. 10, 11. — Valves 

 seen from the side oblong, subquadrangular, greatest height in front, 

 and equalling nearly two-thirds of the length ; anterior extremity 

 well rounded and finely toothed throughout ; posterior obliquely 

 subtruncate ; superior margin sloping backwards, nearly straight ; 

 inferior, almost straight, curving upwards behind ; seen from above 

 the outline is compressed, excessively broken and irregularly 

 spinous. Surface of the valves very irregularly pitted and spinous, 

 beset, especially towards the dorsal margin, with triangular spines 

 of variable size, and within the anterior margin bearing a regular 

 row of about fourteen small rounded tubercles ; hinge-tubercle large 

 and prominent. Length, l-28th of an inch. 



One valve only of this fine and very distinct species has occurred 

 to us. 



CytJierura undata, var. This variety, figured in the " Annals and 

 Magazine of Natural History," loc. cii., from a single recent specimen, 

 occurs more abundantly and in precisely the same condition, in the 

 Post-Tertiary Clay of Portland. 



Cytherura granulosa, nov. sp., Plate II., Figs. 14, 15 — Cara- 

 pace elongated, compressed ; seen from the side subquadrangular, of 

 almost equal height throughout ; height equal to fully one-half of 

 the length ; anterior extremity well rounded ; posterior produced in 

 the middle into a very broad obtusely truncate beak ; superior 

 margin scarcely at all arched, inferior almost straight ; seen from 

 above cuneiform, widest near the posterior extremity, thence tapering 

 gently to the front, which is obtusely pointed, posterior extremity 



