228 
KAUTILOIDEA. 
of the shell, and its bulk is at least double that of the whole of the 
septate portion. The apertural surface makes an angle of about 
45° with the first septum. The larger orifice is a little inclined 
towards the convex border of the shell ; it is nearly circular in con- 
tour, and is connected by a long channel with the smaller orifice. 
The latter is oval in outline, and projects a little beyond the concave 
border of the shell. The septa are approximate, and bend sharply 
upwards towards the shell-wall. The siphuncle is situated at a 
little distance from the ventral border ; its elements are nummuloid 
and flattened. In some examples obstruction-rings (“ anneaux 
obstructeurs ”) are formed upon the necks of the septa. The test is 
somewhat thick, especially around the orifices ; its surface is orna- 
mented with numerous small plications which have a direct imbri- 
cation. In the upper part of the shell they conform to the shape 
of the aperture, and form a shallow sinus on the convex border, 
while on the concave border they present a deep and narrow sinus. 
Hemarks, The affinities of this species have already been dwelt 
upon under G. ventricosum. The specimens from Sweden and Norway 
which I have referred to this species are very imperfect, and appa- 
rently immature, so that I am in some doubt as to the correctness 
of my determination. 
Horizon. Etage E ( = Salopian), Bohemia; Bed 7a (=Wenlock), 
Norway ; Upper Ludlow, Sweden. 
Localities. Konieprus, Bohemia; Norway; Island of Gothland, 
Sweden. 
Eairly well represented in the Collection. The specimen from 
Norway was transferred from the Museum of Practical Geology. 
Gomphoceras imbricatum, Barrande, sp. 
1847. Thragmoceras imhricatnm, Barrande, Haidinger, Berichte fiber 
die Mittheil. von Freund, d. Natiirwiss. in Wien, Band iii, p. 269. 
1848. Cyrtoceras Volborthi, Barrande, ibid. Band iv. p. 208 {fide 
Barrande). 
1867. PJiragmocei'as imhricatum, Barrande, Syst. Sil. de la Boheme, 
vol. ii. pt. i. p. 212, pi. xlvi., pi. clxxv. AT. 1-15, pi. ccxliv. AT. 6-12. 
1882. Thragmoceras imbi'icatum^ Blake, British Foss. Oeph. pt. i. 
p. 202, pi. XXV. AP. 2, 2 a. 
Sp. Char. The shell is curved so as to form nearly half a whorl ; 
its initial point is rounded, and the extremity bears a well-marked 
cicatrix in the centre, and is ornamented with fine concentric striae. 
The transverse section varies a little in different parts of the shell, 
but its form is always either elliptical or oval. The ventro-dorsal 
