0354 Correspondence—F. Chapman. 
species collected, including notes on Productus, Chonetes, Derbya, and 
Orthothetes, contributed by Dr. A. Vaughan, and new species of 
Chonetes, Raphistoma, and Loxonema. 
2. ‘*Brachiopod Morphology: Cincta, Eudesia, and the Development 
of Ribs.” By 8. 8. Buckman, F.G.S. 
The test ornament of Brachiopods is found in three main phases— 
smooth, ribbed, and spinous; and of these three, a costate species is 
more advanced than a smooth one, and less advanced than a spimose 
one. There are catagenetie developments, also, in reverse order; 
but these may, for the present, be neglected. Dall has stated that 
Cineta (Terebratula numismalis Group) is a synonym of Ludesia 
(7. cardium Group); but, although it would be quite possible for 
costate forms to be developed from the smooth Cvncta, yet they 
would not be costate forms of the Hudesia type: in the Cincta type 
the costz developed would be of the kind which produced opposite 
ecarination of both valves, while in Hudesza the costze on the two 
valves are alternate, the carine of one valve being opposed by sulci 
in the other. This fundamental difference not only prevents the 
inclusion of Hudesia and Cincta in one genus, but shows that they 
belong to entirely different series. The first phase of development 
dealt with may be called the lenticular stage, which might develop 
in either of the two directions indicated. The next phase would be 
the Cincta stage, in which the front margin is rounded in youth, 
truncate in adolescence, incipiently excavate and bilobate in the adult, 
as the growth-lines of the specimens show. The Ctncta stage may 
develop in two directions—out of broad forms the quadrifid stage, 
out of narrow forms the cornute stage. The next development may 
be called the quadricarinate or trigonellid stage ; and the fourth stage, 
the multicarinate or pectunculus stage. In KEudesia there is a highly 
developed multicarinate stage, but the carine are alternate, not 
opposite. In degree of ribbing it is higher than Cincta, and in 
a way even higher than the pectunculus stage; but both the ribbing 
and the loop forbid connection with Cincta. The preceding stage is 
exemplified by Zsmenia pectunculocdes. A prior stage may be seen 
in Megerlia Munieri; and, as an example of the incipient uniplicate 
stage, Zerebratula Whitakert may be given. Certain emendations in 
nomenclature appear to be necessitated as a result of this communi- 
cation ; new names are given, and their application defined. A Table 
is added to show the successive stages of development along the 
two lines. 
CORRESPONDENCE. 
CALCAREOUS NODULES. 
Srr,—It is interesting to learn, from Dr. Stopes’ article on the 
relation of the Yarra concretionary nodules and the Lancashire and 
Yorkshire ‘ coal-balls,’ that her recent researches, in conjunction with 
Mr. Watson, promise to settle the question of the origin of the latter 
