40 
NATITILOtDEA. 
give a full-sized figure of this interesting specimen. I may mention ■ 
that it was collected in 1876 by Dr. R. W. Coppinger, who || 
accompanied Lieut. Fulford in his exploration of Petermann Fjord 
(Kennedy Channel), at the mouth of which Offley Island is 
situated. 
I have not been able to find any species resembling this closely 
enough to suggest affinity with it. 
Horizon. Silurian (Niagara Formation). 
Localihj. Offley Island, Kennedy Channel, Arctic America (lat. 
81° 16'). Transferred from the ‘Museum of Practical Geolog)’. 
Orthoceras bullatum, Sowerby. 
1839. Orthoceras hidlatum, Sowerby, in Murchison’s ‘ Sil. Syst.’ p. 612, 
pi. V. f. 29. 
1839. Orthoceras striatum, Sowerby, id. in description of plates, 
p. 612. 
1847. Oiihoceratitessuhstricdus, D'Orbigny, Prodrome de Paleont. vol i. 
p. 54. 
1852. Orthoceras hullatum, M‘Coy, British Pal. Foss. fasc. ii. p. 313. 
1867. Orthoceras hullatum, Dixon, Trans. Woolhope Nat. Field Club, 
Fossil Sketches, No. 1. f. 1. 
1873. Orthoceras hullatum f, Malaise, TeiTain Silurien du Centre de la 
Belgique, p. 89, pi. iii. f. 3. 
1882. Orthoceras hullatum, Blake, British Foss. Ceph. pt. i. p. 129, 
pi. xii. fi*. 4, 5. 
[Not Orthoceras striatum, Sowerby, Min. Con. vol. i. p. 127, pi. Iviii.] 
Char. Section circular, in uncompressed examples. Rate of 
increase 1 in 6, decreasing to almost zero in the body-chamber. 
Septa more or less undulating ; distant from J to -J- the diameter. 
Body-chamber not more than twice its basal diameter in length, 
with a slight contraction below the aperture. Siphuncle central ; 
elements bulbous or bead-like. Surface covered with fine, longi- ; 
tudinal riblets, varying in their aspect according to the preservation 
of the fossil. 
Horizon. Wenlock Shales ; Lower Ludlow ; Upper Ludlow. 
Localities. Dudley, ^ orcestershire ; Ludlow, Shropshire ; Pres- 
teign and Stapleton, Radnorshire ; Hutton-i’-th’-Hay, Benson 
Knot, End Moor, near Milnthorpe, and Kendal, Westmoreland; 
Aymestry, Herefordshire ; Usk, Monmouthshire ; Llanfrechva, 
North (?) Wales. 
Represented by a large series of specimens. 
