KNOWN SPECIES OF MARINE OSTRACODA. 385 



nata, but is so near as to be fairly referable to that species. The recent specimens are 

 deficient in the spines which beset the posterior half of the valves of the fossil species ; 

 and the marginal rows of spines appear also to be less fully developed, though still 

 following the same distribution. 



4. Cythereis militaris, n. sp. (PI. LXI. fig. 9, a-d.) 



Carapace oblong, broadest in front. Anterior margin boldly rounded, gibbous at the 

 dorsal angle. Posterior extremity rounded, narrow. Dorsal margin sloping backwards, 

 much elevated at the anterior hinge. Ventral border rather convex. Dorsal aspect 

 oval, with acutely tapering extremities ; on each valve two spinous ridges, the last 

 spine of each being very long and strong. Surface of the valves smooth and polished, 

 bearing, a little below the centre, a longitudinal row of six or seven spines, the hinder- 

 most of which is very long and pointed. The anterior margin bears a beautifully 

 regular row of similar teeth, twenty in number, commencing at the dorsal protuberance, 

 and ceasing directly below that point on the ventral margin, which is fringed by a row 

 of equally regular but much smaller teeth nearly to the posterior angle, where they 

 give place to four longer, curved spines. The posterior margin is irregularly spinous. 

 The dorsal margin bears a series of seven strong spines, beginning at the anterior hinge 

 and increasing in length from the first to the last, which is situated at a considerable 

 distance from the hinder extremity. 



Length -^ in. ("5 mm.). 



Hab. Hobson's Bay, Australia. 



5. Cythereis laceuata, n. sp. (PI. LXI. fig. 4, a-e.) 



Oblong, subquadrilateral, nearly twice as long as broad. Anterior and posterior 

 margins beset with strong, blunt spines, the former rounded, the latter angular. Dorsal 

 margin arched, highest at the anterior hinge; ventral straight. Dorsal profile oval, 

 spinous in front and behind. Surface of the shell wrinkled, covered with elevated, 

 sinuous laminas, the edges of which are irregularly waved or jagged. On each valve 

 three or four of these laminse are strongly developed, one of them forming a strong 

 dorsal ridge. 



Length -^ in. (84 mm.). 



Hab. Abrolhos Bank. 



6. Cythereis fungoides, n. sp. (PI. LXL fig. 7, a-d.) 



Quadrangular, trapezoid, convex. Dorsal and ventral margins parallel, irregularly 

 cut and waved. Extremities oblique, slightly rounded, unequally dentate. Dorsal 

 aspect broadly oval, angular, displaying three longitudinal ridges on each valve ; the 

 hinge-margins or keel broad, much expanded and angular posteriorly. Surface of the 



VOL V. PART V. 3 e 



