Co rresp ondence. 127 
th(,' point of view takfii tiicn by professor Hyatt or now by Dr. IJather: 
but, though appreciating its premises, 1 am nevertheless impressed by 
its serious improbability . Tlie possession of this fossil was not a men- 
incident. By assiduous effort and by every mechanical and chemical 
contrivance known to me, I have for many years endeavored to wring 
the fossil contents from this heretofore little studied formation of the 
Genesee shales. This is one of the results, and while, among Die others, 
cephalopod protoconchs and ])rotoconch-bearing shells abound, it would. 
I submit, after this protracted (Effort, be somewhat less than likely that 
a genus of cephalopods in these faunas should still be known by its pro- 
toconch alone. There are h<'re Mantirocercts, (jlephyroreruK, Tor-noccran, 
and perhaps some otiier forms of the goniatites. Clynienia, Ihtctriten. 
Gomphoco'ax and Orfftori'nix. The jiossible variations in the form of 
the protoconch within tlie limits of a grouj) of allird genera or even of a 
given genus arc not yet satisfactorily rstablished. I-'rom our i)resent 
knowledge and presumably, tiicy arc not grcal. This [iroloconcli is 
assuredly not that of any of thi' goniatiline genera mentioned, nor of 
(Jlyiaenia, which I have fully desciil>ed, nor that of Bacfriti'K. uidess 
these primitive shells vary in all essential ))articulars with the species. 
One may readily admit the suggestion of leather that many of the 
things termed Ort/iorcvax may pi-o\f to be something else than typical 
orth(JCerans: I may, however, remark from my knowletlge of liic orlho- 
ct-rans of this fauna thai they have not fxinced any dissimilaril.x from 
such typical forms. 
A recent expression from INof. Hyatt eoii\eys the impression that the 
facts above stated and thi' evidence from the fossil itself which he has 
since examined has somewhat modified his opinion. In his latest and 
very remarkable paper, tin- "Phylogeny of an Acquired Characteristic," 
lie writes (p. :U)1): "Clarke has recently shown that a straight, Ortho- 
ceras-like shell may have a complete egg-shai)ed protoconch likelhatof 
Hactrites. His form certainly has the characters of an Orthoceras, but 
the |)rotocoiu'h is hirge and like that of the .\mnionoidea. The sliell 
may lie transitional from Orthoceras to liactrites but is probably not a 
typical form ofOrthoceras.'" At this writing I believelliat l'rt)f. Hyatt 
did not have before' him my account of the "I^^arly Stages of JJactrites," 
and I must here rehearse the fact, the force of which liather iiimself 
seems not fully to have recognized, that the whole and entire .-irgumeiit 
for regar<liiig Jhntritix as a straight ammonoid shell rests upon liraiu'o's 
determination of a .)fiiiiiic(r(ts-\\k<- pnitoconch in shells which In IxUircd 
folic nid-trifis. l)iit whose niatnie charaelers wen' unknown. Herein 
till- material described by nie h.-is a (ji'cided a(l\;intage: it was abundant 
and its characters at every growth -stage from incept ion to maturity an- 
known, its later phases showing it to be in fuil agreement with the 
species ui)on wliicli the genus was founded. Disavowing any intention 
of casting doubt upon the ol)servat ions of Dr. Hranco, I thiid< it clear 
that the Bdrtriti'm which ha\e lieen described l)y nu' are a stei) further 
away from the (JoniatitinM- and nearer the nautiloids than the Miiiiorrnix- 
like shell (lescribi'd by liiin. 'i'iie New \'oik sjiecinieiis of /inrtn'trx 
