OF SOFTHEEX INDIA. 
7 
the surface ; luumal valve jiatcUiform, witli a suh-central or escentric vertex ; outer 
surface smooth, couceiitrically or radiatcly striated or rihhed, inner with two suh- 
central anterior and two suh-marginal posterior adductor scars, tlie two in each 
pair respectively distant from each other ; neural valve with two approximate suh- 
central anterior scars, generally separated hy a dentiform, more or less prominent, 
ridge, and with two distant suh-marginal ])osterior scars ; all the scars are rounded 
or roundish oval, and either somewhat impressed or situated on special thickenings 
of the shell ; the neural valve generally has a narroAv indistinct area at the poste- 
rior, somcAvhat trmicate, edge ; vascular impressions in both valves single, digiti- 
form. (For the history of the genus, and the sub-divisions suggested hy various 
authors, I must refer to Mr. Davidson’s elaborate account in his classification of 
the Brachiopoda). 
The species of Crania occur from the oldest sedimentary formations up to the 
present time. They appear to have been, however, most numerous dm-iug the 
cretaceous period. Of recent species II. and A. Adams quote five, hut the type 
of the genus is a cretaceous one from Maastricht, Crania Braltenhiirgensis, 
(Stohmus). 
In the cretaceous rocks of Southern India a single species has as yet occurred, 
and this is a very widely distributed one, originally described hy Ft otzius, the founder 
of the genus. 
A list of the cretaceous species, as far as known, has been given hy Schloenhach 
in the “ Palseontograpliica,” Cassel, 18G6, vol. XIII, pt. "N'l, p. 317 ; they are all 
European, or at least from the old continent ; no species has, I believe, been as yet 
described from America. 
Craxia Ignabergexsis, Betzius, PI. I, Figs. 1 — 2. 
1781. Crania Ignahergmsis, Retzius, Scliriften cler Berl. Akademie, II, p. 75, pi. I, figs. 4 — 7. 
1847. eadem, d’Orbigny, Pal. Fran?, ten-, cret., IV, p. 141, pi. 525, figs. 1 — 6. 
1852. Crania Egnahergensis, apud Davidson, British Cret. Brachiopoda, p. 11, pi. I, figs. 8 — 14 (cum. syn.). 
1800. „ Ignabergen^is, „ Schlojnhach, ‘ Palocontographica’, 1806, XIII, p. 320 (cum. sj'u.). 
Testa snhquadrangiUariter rotundata, sen rolundata, incequivalvi ; valva netirali 
atit planiuscula a%d convexiore, solum 'proqm apicem excenlricum, seu parte majore, 
affixa ; valca licemaU conoidea, patelliformi, plus minusve elecata, apice acutato, 
excentrico, nonnunquam suhmammillato instructa ; superficie utriusque ralcce costulis 
21-16, radiantibus, majoribus et minoribus alternantibus, striis concentricis intersectis, 
nonnunquam rugidatis seu imbricatim asjqerulatis, ad peripheriam pafido projicienlibus, 
ornata ; margine interno lato, subpiano, gramdalo. 
The neural valve is always attached, either hy the apex or hy a larger or smaller 
portion of its surface ; it is also less convex than the haemal or upper valve, in which 
the exccntric apex is directed somewhat posteriorly. All the muscular scars arc 
situated on considerable thickenings of the shell. The two anterior scars in the 
haemal valve are either entirely separated hy the median ridge, or they meet with 
each other in front of it. 
