KNOWN SPECIES OF MARINE OSTRACODA. 375 
over the central portion in an angular network ; but towards the margins the pattern 
becomes more lax, longitudinal rows taking the place of the meshes. 
Length 75 in. (63 mm.). 
Hab. Norway (Messrs. M‘ Andrew and Barrett’s dredgings). 
Cythere kostelensis, Reuss, as figured by Egger (Die Ostrak. der Miocan-Schicht. t. 4. 
fig. 4), is very similar in form and general characters to our C. catenata. Reuss’s 
original figure is, however, very different; and both authors concur in ascribing to 
C. kostelensis a pitted surface, the former adding that minute tubercles are found 
between the ‘‘ thickly set pores,” which on the ventral surface are replaced by delicate 
furrowings. C. catenata, however, is wholly devoid of pittings, and is ornamented only 
with minute projecting spines or bosses. 
? 
10. CyTHERE SEPTENTRIONALIS, n. sp. (Pl. LX. fig. 4, a—f.) 
Oblong, subquadrilateral, convex. Anterior margin broad and obliquely rounded ; 
posterior narrower and somewhat flattened. Dorsal margin straight, with a slight 
convexity in the middle, and sloping gently backwards from the anterior hinge. 
Ventral margin somewhat convex. Surface marked with large angular pittings, 
which gradually coalesce towards the margins, forming on the ventral surface sharply 
cut longitudinal furrows. The pitted or reticulated sculpture prevails on the central 
parts of the dorsal and lateral aspects; but over the whole ventral surface longitu- 
dinal grooving only is visible. Dorsal aspect ovate. End view broadly ovate, flattened 
and grooved below. 
Length 35 in. (1:27 mm.). 
Hab. Hunde Islands, 60-70 fathoms (Dr. P. C. Sutherland’s dredgings). Many 
specimens. 
This is possibly allied to a Tertiary (Eocene) species, C. scrobiculata, Minster. 
There is, indeed, less difference between the recent C. septentrionalis and some 
figures of the fossil C. scrobiculata than between some of the fossil forms referred 
by different authors to the latter species. Dr. Baird remarks also that his C. quadri- 
dentata is nearly allied to C. scrobiculata as originally described by Von Minster. It is, 
however, very widely different from the present species. The marks which I should 
especially insist upon as diagnostic of C. septentrionalis are the strong development of 
the anterior hinge, and the oval outline and distinct longitudinal fluting of the ventral 
aspect. But the whole group to which it belongs is a perplexing one, its various 
members running into each other by imperceptible gradations, which, to my mind, 
speak plainly of one common origin. 
11. Cyruere costata, n.sp. (Pl. LX. fig. 5, af.) 
Carapace compressed, oblong, narrowed posteriorly. Anterior margin rounded, and 
