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 8p. Moscpcensis, 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 Sjo. triangularis appear to be 
good species. Sp. hisulcata 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. hisidcata. It is even a question requiring further 
examination whether Sp. trigonalis should be considered separate ; 
and, although Sp. convohUa is a wonderfully transverse and curious 
shell, I am not yet quite satisfied that it is not likewise related to 
S. hisulcata. Sp. rhomhoidea, 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 Sj). 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 
\vill do well in searching for more specimens. Sp. cuspidata is a 
good species, distinct from Sp. distans ; to which last I would 
unite Sp. hicarinata, 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 Sj). 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 w^as 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. ovalis and Sp. 
integricosta, 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. ^ZaZ>m 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 
