4 CARBONIFEROUS CEPHALOPODA OF IRELAND. 



chamber ; excentric, situated at a point whicli is about two-fifths of the distance 

 across the longer diameter of the shell. Test smooth. 



Size. — Length of the largest specimen met witli about 600 ram. ; greatest 

 diameter 67 mm., least 6 mm. 



Affinities. — Orthoceras Leinsterense most nearly resembles this species, but the 

 two are very easily distinguished. In 0. Leinsterense the septa are remarkably 

 approximate in the earlier and middle portions of the shell ; in 0. Colei, on the 

 otlier hand, the septa are more regularly spaced, their distance apart increasing 

 gradually with the growth of the shell. The rate of tapering in the present 

 species is also higher than in 0. Leinsterense. I find none of de Koninck's species 

 comparable with the present one. 



Bemarlcs. — Only two or three specimens of this species have been obtained up 

 to the present time, but they present constant characters, which may be easily 

 recognised when suitable means are taken to develop them. These consist in the 

 preparation of sections, longitudinal and transverse, the former being of special 

 importance, as it is necessary to ascertain the structure of the siphuncle and its 

 relation to the septa, as well as the characters of the latter. My experience has 

 taught me that very few species of these straight-shelled cephalopods can be 

 determined by the external characters alone, except in cases where there is a well- 

 marked ornamentation. The species is named after Professor G. A. J. Cole, 

 F.G.S., of Dublin. 



Locality. — Clane, county of Kildare. 



Orthocekas Xolaxi, A. H. Foord. Plate III, figs. 1 «— /. 



1&96. Ortuoceras Xolaxi, 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. 20. 



Description. — Shell straight, elongate, tapering at the rate of 1 : 7. Body- 

 chamber about one-fourth of the length of the entire shell, with a well-marked 

 constriction posterior to the aperture. Section elliptic, partly if not wholly by 

 compression, the ratio of the two diameters being as 4 : 3. The septa are 

 moderately distant, being 10 mm. apart where the shell diameter reaches 32 mm., 

 this distance increasing to 15 mm. where the diameter is 42 mm. The chambers 

 are deep, but not so deep as they appear to be, owing to the compression of the 

 shell, which has pushed the septa inwards, Ijringing part of them nearly parallel 



