252 
NAUTILOIDEA. 
fine transverse lines upon the surface, which may be seen with the 
aid of a lens ; they are regular, and number from 2 to 3 in the space 
of a line. 
RemarTcs. Ascoceras Yerneuili is almost the only described species 
of the genus having a straight form, without being infiated in the 
middle, nor constricted above. It is distinguished also by the very 
short distance which separates the aperture from the last septum. 
Horizon. Etage E (= Salopian), in white limestone. 
Locality. Dlauha Hora, Bohemia. 
Eepresented by a few very imperfect specimens. 
Ascoceras Bohemicum, Barrande. 
1855. Ascoceras Bohemicum, Barrande, Bull. Soc. Geol. de France, 
vol. xii. p. 174, pi. V. IF. :20-28. 
1855. Ascoceras Bohemicum, Barrande, Leonhard and Bronn’s Jabrb. 
p. 277, pi. iii. ft'. 1-8. 
1867. Ascoceras Boheinicum, Barrande, Syst. Sil. de la Bolieme, vol. ii. 
pt. i. p. 354, pi, xciii., pi. xciv. if. 28-37, pi. xcvi. ft*. 46-49. 
1877. Ascoceras Bohemicuon, Barrande, ibid. vol. ii. Suppl. et S^rie 
tardive, p. 97, pi. ccccxciv. ft'. 14, 15. 
? 1882. Ascoceras Bohemicumy Blake, British Foss. Ceph. pt. i. p. 208, 
pi. xxvi. 
Bp. Char. This species (fig. 41) attains larger dimensions than 
any of its congeners. The shell presents a very considerable con- 
vexity upon the side on which the body-chamber lies, and a distinct 
concavity upon the other side. The transverse section taken about 
the mid-length is oval, of which the ventro-dorsal is to the transverse 
axis in the ratio of 5 to 4 ; the principal part of the fossil is therefore 
considerably flattened. Just above the last septum a constriction 
occurs and the shell terminates in a sort of cylindrical neck, which 
is about 4 of the total length of the fossil, its diameter being about 
§ of the maximum width. The aperture is circular, and placed a 
little obliquely with reference to the longitudinal axis of the shell 
(fig. 41, «). The body-chanaber is excessively contracted by the 
encroachment of the septal chambers just above the mid-length of the 
shell, so that it is here not more than 4 of the width of the fossil. 
The number of septal chambers varies from 4 to 5 in specimens 
where these can be accurately observed, and this variation in their 
number seems to have no connection with size or age, for very small 
as well as large specimens are found with 5 chambers. The latter 
are very unequal in size, as wiU be seen on referring to the figure 
of the species (fig. 41 a, &c.). The lower or dilated part of the 
