52 



THE GEOLOGIST. 



Spirifera. — Twenty-five species (?) are here provisionally retained, 

 for the reasons already given, viz., the want of sufficiently certain 

 connecting links ; but it is highly probable that with time and study 

 some few of these may be dispensed with, or retained as mere varieties. 

 Martin's Spirifera striata is the largest and most typical form of the 

 genus, and must therefore always be considered a good species ; but 

 I would recommend a further study of Sp. Mosquensis, Sp. humerosa, 

 and Sp. duplicicosta, in order to ascertain whether they are also good 

 species, or modifications of Sp. striata; for I confess that many examples 

 of the three last-mentioned species could be but doubtfully separated 

 from Martin's shell. Sp. planata and Sp. triangularis appear to be 

 good species. Sp. bisulcata has varied considerably in form ; and 

 I am quite disposed to agree with my friend, Prof, de Koninck, in 

 the idea that Sp. crassa and Sp. grandicostata are simple modifications 

 in the shape of Sp. bisulcata. It is even a question requiring further 

 examination whether Sp. trigonalis should be considered separate ; 

 and, although Sp. convoluta is a wonderfully transverse and curious 

 shell, I am not yet quite satisfied that it is not likewise related to 

 S. bisulcata. Sp. rhomboidea, Phill., is still an uncertain form, of which 

 my material has been too scanty ; and as I am uncertain whether I was 

 justified when uniting it to Sp. convoluta, it will be better for the pre- 

 sent, at least, to retain it as separate. Of Sp. fusiformis but a single 

 fragmentary specimen has been hitherto discovered, so that its 

 specific claims cannot be definitely admitted. 



Sp. mesogonia is also a rare shell, for I have never seen of it more 

 than the figure in the " Synopsis;" and Irish geologists and collectors 

 will do well in searching for more specimens. Sp. cuspidata is a 

 good species, distinct from Sp. distans ; to which last I would 

 unite Sp. bicarmata, which M'Coy established on a single imperfect 

 specimen from Cork, in the possession of Dr. Haimes, and which has 

 much of the appearance assumed by certain examples of S. distans. 

 Sp. triradialis is a good species, but very variable in the arrangement 

 and number of its ribs ; and of which the Sp. trisulcosa and Sp. sexra- 

 dialis of Phillips are evident modifications. Sp. Beedii must be 

 looked upon as a doubtful species, requiring, perhaps, to be here- 

 after expunged ; my material was very scanty, and I have since had 

 doubts as to its validity. Sp. pinguis is a good but variable species, 

 into which should perhaps be combined, as varieties, Sp. oralis and Sp. 

 intcgricosta, for many intermediate shapes are often found, so much 

 so that the palaeontologist is often puzzled how to determine with 

 which of the three they should be located; but, the larger number 

 of specimens being tolerably distinct and easily recognisable, we may 

 be excused for provisionally retaining the three denominations. 



Sp. glabra is another excellent species, or a type round which are 

 clustered many modifications not sufficiently marked to constitute 

 separate species; for, although the typical form of Sp. glabra possessed 

 smooth valves, it is not uncommon to find in other examples faint 

 indications of lateral plication, or obscurely flattened or slightly 

 rounded ribs, the fold and sinus remaining always smooth. These 



