:5s The American Geologist. July, 1894 
Goniatitinse, except in the genua Mimoceras ( Goniatites com- 
pressus), Where, in addition to this peculiar form of the pro- 
toconch, the initial portion of the shell-tube is straight, the 
primary volution free and the umbilicus open. Before the 
record of this observation, considerable divergence of opinion 
had been expressed by authors as to the phyletic position of 
Bactrites,* many choosing to associate it with Goniatites 
among the ammonoids. Beyrich (1851) regarded the genus as 
an orthoceran with marginal sipho, and this view was shared by 
F. Eoemer, Owen and Quenstedt. In 1877 Barrande figured} 
as Bactrites hyatti, what was believed to be the initial ex- 
tremity of a specimen which had been found in the Munich 
university collection, labelled B. gracilis Sandberger, and 
drawings of which had been prepared for him by Hyatt. 
These figures, however, show that the specimen bears no pro- 
toconch, but begins with a tapering, conical chamber having 
a cicatrix on its distal surface. Branco. in 1880 (Palseonto- 
graphica, ut cit.), while expressing some doubt as to the gen- 
eric relations of the Munich specimen, stated his conviction 
that, should this prove a genuine Bactrites, there could 
then be no question of its close affinity to Orthoceras. The 
description of the Wissenbach protoconchs a few years later 
dispelled this view. 
An anticipatory glance at the figures here given of proto- 
conch-bearing specimens of Bactrites will serve to show not 
only a difference in the form of this body and that ascribed 
to the genus by Branco. but also the very close similarity be- 
tween it and that of Orthoceras, as given by the writer, and 
that of Belemnites as given by Branco.* These differences in 
the initial stages of shells ascribed to Bactrites lead first to 
the inquiry as to which of all these specimens really belong to 
this genus, for it would seem that all cannot. Branco showed§ 
at some length and quite conclusively that the Munich speci- 
men figured by Barrande could not be accepted as a repre- 
sentative of this genus. With equal lucidity he indicated the 
*For a summary of these opinions see Branco, Palseontographica, vol. 
27, p. 19, L880. 
(■Cephalopod.es: Etudes Generates, pi. 490, fig. 1; i>. 120. 
jZeitechrift der deutsch. geol. Gesellsch. vol. 32, p. 608, fig. 7, 1880; 
also Palaeontographica, ut cit. 
gZeitschr., ut cit. vol. 37, 1885 
