ORTHOCERAS PILUM. 13 



Orthoceras subclavatum, A. H. Foord. Plate IV, figs. 2 a — c. 



1896. Orthoceras subclavatum, A. H. Foord. Ueber die Orthoceren des 



Kohlenkalk3 (Carboniferous Limestone) 

 von Irland. . . . Iuaugural-Disserta- 

 tion zur Erlangung der Doktorwiirde 

 der Kgl. bayer. Ludwig-Maxi- 

 milians-TJuiversitat zu Miinchen, p. 2±. 



Description. — Shell rather short, increasing at the rate of 1:6. Section 

 elliptic. Ratio of the two diameters 4 : 3. Body-chamber nearly one-third of the 

 length of the whole shell, somewhat fusiform, its base oblique to the longitudinal 

 axis of the shell. Septa oblique, very numerous, about 4 mm. apart where the 

 diameter of the shell is 25 mm. Siphuncle inflated between the septa in a bead- 

 like manner. Shell smooth, its thickness on the body-chamber amounting to about 

 1*5 mm. 



Size. — The length of the only example known amounts to 215 mm. ; the 

 greatest diameter to 38 mm., the least to 6 mm. 



Affinities. — This species is distinguished from Orthoceras Hindei by its more 

 slender form, much closer septa, and smaller siphuncle. From Orthoceras 

 Breynii, de Kon. (not Martin), it differs in its more rapid tapering and wider 

 septation. 



Remarks. — This form reminds one at first sight of a Poterioceras in the 

 straightness of one side and the curvature of the other, the close and very oblique 

 septa, beaded siphuncle, and the slightly fusiform outline. On the other hand, 

 the almost central position of the siphuncle and the want of any contraction of 

 the body-chamber near the aperture, added to its slender proportions, dispel the 

 idea at first conceived of its affinities. 



Locality. — Little Island, near Cork. 



Orthoceras pilum, A. H. Foord. Plate V, figs. 3 a, b. 



1896. Orthoceras tilum, A. H. Foord. Ueber die Orthoceren des Koklen- 



kalks (Carboniferous Limestone) von Irland. 

 Inaugural-Dissertation zur Erlangung 

 der Doktorwiirde . . . der Kgl. bayer. Ludwig- 

 Maximilians-IJniversitat zu Miinchen, p. 24. 



Description. — Shell straight, somewhat rapidly increasing, the ratio being about 

 1 : 6. Section elliptic. The ratio of the two diameters nearly as 4 : 3. Body- 



