CYKTOCEEATID^. 
273 
imperfect, but they agree tolerably well with the above description 
and with Sowerby’s and Blake’s figures. The section is seen to be oval. 
Horizon. Wenlock. 
Locality. Dudley, Worcestershire. 
Eepresented in the Collection by two imperfect specimens. 
Cyrtoceras (Meloceras) isca, Blake, sp. 
1882. Cyrtoceras isca, Blake, British Foss. Ceph. pt. i. p. 174, pi. xix. 
ff. 6, 7. 
Bjy. Char. “ The section is elliptic, the diameters in the ratio of 
24 to 19, the longer one in the plane of curvature. The curvature 
is never great, the type having a maximum. The rate of increase is 
rather greater than 1 in 4. The ornaments are direct, forward 
imbrications, from | to a line apart, convex towards the aperture. 
These cease on the body-chamber, and give place to lines of growth. 
There is some appearance in one specimen of the aperture having 
been contracted like a Phragmoceras, but there is no other change in 
the shape of the body-chamber. The septa are very slightly convex, 
very close and sigmoid. The siphuncle in all is external and bulbous.” 
{BlaJce.) 
RemarTcs. Prof. Blake compares this species with C. fortiusculum, 
Barr., with which it agrees in ^‘the closeness of the septa, the 
position and form of the siphuncle, and the general rate of increase 
but, he observes, Barrande’s species is smooth, this one is orna- 
mented. “It has also its sutures sigmoidal, and perhaps even 
closer, and its curvature is less.” 
Horizon. Lower Ludlow. 
Locality. Sedgeley, Staffordshire. 
Eepresented in the Collection by one imperfect example. 
Longicon-es k 
Cyrtoceras (Meloceras) ambiguum^ Barrande, sp. 
1848. Cyrtoceras ambiguum, Barrande, Haidinger, Berichte fiber die 
Mittheil. von Freund, d. Naturwiss. in Wien, Band iv. p. 209. 
1852. Cyrtoceras amhiguum, Giebel, Fauna der Vorwelt, Band iii. 
Abth. i. p. 209. 
1867. Cyrtoceras amhiguum., Barrande, Syst. Sil. de la Boheme, vol. ii. 
pt. i. p. 482, pi. clviii. ff. 1-21, pi. cciii. ff. 7-10. 
^ The series of Bohemian species in the Museum Collection is sufficiently 
numerous to be divided into Longicones and Brevicones, according to Barrande’s 
grouping. 
T 
