SUPPLEMENT\ 
Genus ORTHOCERAS^ 
SILURIAN SPECIES. 
OrthoceraS) sp. 
This specimen (Ho. C. 2977) is a fragment of the septate part of 
the shell, partly hidden in the matrix. The shell tapers rather 
slowly ; the section is circular ; the septa are very numerous, there 
being 24 in the space of 2J inches. The siphuncle is not seen, and 
there is no trace of the test. 
Horizon, Silurian (Lower Ludlow). 
Locality. Mlaszkowce on the Sered (or Sereth), Galicia. 
Presented by Dr. Szajnocha. 
Orthoceras, sp. 
Two fragments (Ho. C. 2976 & 2978) apparently belonging to the 
same species, but too imperfect to be determined specifically, may 
be thus described : — Shell very slightly curved. Transverse section 
circular. Rate of increase about 1 in 8. Body-chamber unknown. 
The distance between the septa increases slowly and somewhat 
irregularly ; they are from 2 to 2J lines distant from each other 
where the diameter of the shell is about 13 lines ; the sutures are 
slightly undulating. The siphuncle is central. 
EemarTcs. The specimens here described are casts of the septate 
part of the shell, without any of the test remaining. They were 
presented to the British Museum (October, 1888), together with 
some other specimens of Orthoce7'as, by Professor Dr. Szajnocha of 
Cracow (Krakow). AU the specimens are accompanied with labels 
^ Consisting of species added to the Collection during the progress of the 
present volume; together with some notices of recent works on the genera 
treated of in tliis, and the First Part of the Catalogue. 
^ See Part I. of the present Catalogue, p. 1. 
