272 
PALEONTOLOGY OF NEW YORK. 
“ The upper edge where viewed from the side, is flatly roof-shaped, while 
the lower edge describes two convexities, the greater anterior, leaving a notch 
between them. The surfaces of the loop and median plate are covered with 
minute, obliquely conical pustules, in some cases seeming to become 
spinulous.”^ 
Forms with this characteristic modification of the loop may be designated 
by the term Romingerina.I 
After the disappearance of the Palaeozoic faunas, we again find in the Alpine 
Trias (Hallstiltter-kalk) smooth, biconvex centronellids, less complicated in the 
structure of the brachidium than Romingerina, even having the brachial sup¬ 
ports smaller and more delicate, if not more simple in plan, than in Selenella. 
These shells have been described by Bittner {loc. cit., p. 206. 1890) under the 
generic term Juvavella. Their brachidia are very short, the lateral branches 
but slightly expanded anteriorly and abruptly turned into a vertical plane. 
We may now turn to the consideration of the plicated centronellids which 
have already been closely investigated by (Ehlert, and have received attention 
from Waagen, Derby and Davidson. This discussion would with propriety 
form a continuation of the observations already made upon the genus Rens- 
SEL^RiA, for it is the plicated and lineate shells of that genus which represent 
the earliest appearance of the CENTRONELLA-type. The lower Devonian species, 
from the west of France, in which Dr. (Ehlert has determined the existence 
of a centronellid brachidium, are all biconvex or subplano-convex species; 
Terebratula Guerangeri, de Verneuil, is covered with strong rounded plications, 
Centronella Gaudryi, CEhlert, with numerous fine plications, while on C. Bergeroni, 
(Ehlert, there are a few coarse angular ribs. All have a decided external 
resemblance to certain spire-bearing forms of the genera Rhynchospira, Tre- 
MATOSPiRA and Zygospira. The brachidium has been isolated in none of these, 
but sections demonstrate that this structure in all these forms is similar to that 
* Pj’OC. Acad. Nat. Sci. Philadelphia, p. 405. Ife62. 
t Di-. Carl Rominger, to whom this genus is dedicated, was the first American investigator who suc¬ 
ceeded in producing satisfactory ti-anslucent prei)arations of the fossil brachiopods with calcified brachidia. 
Many of the determinations published in the Reports on the New York State Cabinet from 1861-67, and in 
Volume IV of the Palfeontology of New York, as thei-e recognized, were based upon his preparations. 
