148 
NAUTILOIBEA. 
annulations, of which six or seven are contained in the space of 1 inch, 
are crossed transversely by raised, thread-like lines, which run 
parallel with them. About three of them are contained in the space 
of 1 line ; they are usually a little wider apart upon the annulations 
than between them (see fig. 15). 
Bemarks, This species was first figured by Hisinger in the An- 
teckn. i Physik och Geogn. (loc. cit.) in a somewhat unsatisfactory 
manner as regards the finer surface ornaments, which are represented 
as consisting of only two transverse striae to each of the annulations, 
instead of six or seven. In other respects this figure gives one a 
better idea of the shell than does the one in the ‘ Lethaea Svecica,’ 
because a greater length of it is shown, and thus the rate of increase 
can be better estimated ; this amounts to 1 in 12. 
Hisinger has added at the end of his description of E. trochleare^ 
“ Orthoceras vaginatus ?, Schloth.” In consequence of this many 
authors have supposed these two species to be identical. It has, 
however, been clearly shown by Eichwald that Schlotheim’s species 
is perfectly distinct from E. trochleare. The frequent occurrence of 
the name vaginatuin in my synonymy of the present species is thus 
explained. 
The figures given by Klein ^ very probably represent E. troclileare. 
I have om tted from the synonymy of this species “ Cycloceras 
trochleare,” Eichwald, which name it is proposed by Noetling 
Schmidt, and Inostranceft’ to cancel, those gentlemen having failed 
to find the original specimen (figured by Eichwald, Leth. Boss. pi. li. 
IF. 23, a, 6) in the “Eichwald Collection” at St. Petersburg, and 
not deeming Eichwald’s description sufficient for identification. 
Both Eichwald’s form and the one figured by Karsten {loc. cit. f. 7 h), 
are closely allied to Orthoceras hifov eat am., Koetling (Zoc. aA p. Ill), 
and consequently they do not belong to the same genus as E. troch- 
lear e. 
Horizon. GriAor<^r«s-Limestone (=Arenig), Sweden. Ardwell 
Group (Middle Bala), Scotland. 
Localities. British. Ardwell, Ayrshire. — Foreign. Gerhz (Kop- 
parherg ^), and Skyrbergn,' Sweden. 
Represented by several remarkably fine specimens. 
' Tubulorum Marinorum, 1731, Species ii. Circulis asperi, Append, p. 11, 
Tab. vi. ff. 1-5. 
^ Jahrb. der konigl. preuss. geol. Landesanst. und Bergakad. zu Berlin, fiir 
das Jabr 1883, p. 115. 
* The ancient province of Dalecarlia or Dalarne. 
I 
