ORTHOCERAS PORTERI. 9 



. . . Inaugural-Dissertation zur Erlangung 

 der Doktorwiirde . . . der Kgl. bayer. 

 Ludwig-Maximilians-Universitat zu Miinchen, 

 p. 16. 



I have identified a specimen from St. Doulagh's with this species with some 

 doubt ; it agrees best with de Koninck's figures on pis. xl and xlii of his work. 

 The figure on pi. xxxix, fig, 7, represents a shell with a more rapid rate of 

 tapering than is seen in the figures on the other plates, or in the specimen from 

 St. Doulagh's. 



Orthoceras calamus, de Koninclc. 



1880. Oethoceeas calamus, L. G. de Koninck. Faune Calc. Carb. Belgique 



(Ann. Mus. Roy. d'Hist. Nat. Belgique, ser. 



Paleont., vol. v), pt. 2, p. 52, pi. xxxviii. fig. 6. 

 1896. — — A. H. Foord. TJeber die Orthoceren des Kohlen- 



kalks (Carboniferous Limestone) von Irland. 



. . . Inaugural-Dissertation zur Erlangung 



der Doktorwiirde . . . der Kgl. bayer. 



Ludwig-Maximilians-Universitiit zu Miinchen, 



p. 16. 



This species is easily recognised by its great length and slenderness, and by its 

 proportionately wide-apart septa. Two specimens have occurred, both of which 

 are from St. Doulagh's, county of Dublin. The most complete of these is 155 mm. 

 in length, 16 mm. at the widest, and 2*5 mm. at the narrowest extremity. 



Orthoceras Porteri, .4. H. Foord. Plate IV, figs. 1 a — d. 



1896. Orthoceras Porteri, A. H. Foord. Ueber die Orthoceren des Kohlen- 



kalks (Carboniferous Limestone) von Irland. 

 . . . Inaugural-Dissertation zur Erlangung 

 der Doktorwiirde . . . der Kgl. bayer. 

 Ludwig-Maximilians-Universitiit zu Miinchen, 

 p. 14. 



Description. — Shell elongate, slender, tapering at the rate of 1 : 9. Section 

 elliptic, the ratio of the greater to the lesser diameter as 4:3. Body-chamber 

 slightly exceeding one-fourth of the entire length of the shell in a specimen of 



2 



