VINE: CARBONIFEROUS ENTOMOSTRACA, ETC. 
ill the interior of each valve by a tubercle, pit, or group of spots, or 
by both spots and a pit. The branchia are attached to the posterior 
jaws, and there are only two or three pairs of feet, which subserve 
locomotion, but are not adapted for swimming-." * 
The Ostracoda are divided into several families, some of which 
are wholly made up of fossil genera, others are composed of both 
fossil and i-ecent genera. They aie as follows : — 
Family I. — Cvpkid.«: 12 Genera, one of which is Bairdia. 
„ II. — Cytherid^ : 17 Genera two of which contain only fossil species : 
Thlipsura and Carbonia. 
„ III. — Cypriuinad.15 : 9 Genera, three of which contain only fossil 
species : Cypridella, Cyprella. and Entomis. 
,. lY. — Entomoconchid^ : 2 Genera, one of which, ENTOMoco>'cms, 
contain only fossil species. 
„ V. — CoNCH^ciAD^ : 2 Genera. 
„ VI. — PoLY'COPiDJE : 1 Genus. 
„ VII. — Cytherellid.i: : 3 Genera, two of which, Cytiierellina, and 
^ciiMiNA, contain only fossil species. 
,, VIII. — Leperditiad.*) : 0 Genera, the whole of which contain fossil 
species only : Leperditia, IsocmLiNA, Primitia, Beyrichia, 
KiRKBYA, and MooREA.f And the last family, so far as is 
at present known, contain only Pala)ozoic forms. 
Family I. CYPRID^. 
Genus bairdia, McCoy. 
1844, Syn. Charact. Carb. Limst. Foss., Ii-eland. 
" Carapace valves externally convex and smooth, sometimes 
finely pitted or spined, never ribbed or granulated. The hinge is 
simple, no bar or teeth similar to those of Cythere proper, being 
developed. Bairdia is characterised, as regards the carapace, by a 
somewhat similar formation of valves to that which obtains generall}^ 
amongst the recent Cyprides^ and partially in the Candonm.''' Jones, 
Entomos. Cret. Formation, p. 224 
Professor McCoy described the genus very briefly, thus : — 
*' shell elongate, fusiform, suddenly tapering at both ends ; a very 
short proportion of the valve overlaps the abdominal margin." 
Since these works were published a large number of recent and 
fossil forms have been discovered and described, and most important 
* Nicholson i\Ianual of Palaiontology, Vol. I. j). 341, Ed. 1879, 
t Bivalved Entomostraca, Prof. T. Rupert Jones, Monthly Microscopic 
Journal, Oct. 1870, Part I. 
^ J Palacontograj^hicul Soc, 1849. 
