DAVIDSON — ON BRITISH CARBONIFEROUS BRACHIOPODA. 
57 
without that success I had anticipated, I must leave the matter as an 
open question, notwithstanding the advantages I had of being able 
to examine the original specimens or fragments upon which the so- 
termed Irish species ? have been founded. 
Crania. — Three species have been retained; but of these G. 
quadrata is the only satisfactorily determined species. Of Crania ? 
trigonalis I have never seen more than the original type, and it is still 
uncertain whether it is a Brachiopod, notwithstanding that we are 
acquainted with several similarly striated or costated species in the 
rocks of other periods. Of Crania ? (Patella) Ryckholtiana de Koninck 
= C. vesicular is, M'Coy, I am acquainted with but a single Irish 
specimen; but the shell would appear to be less rare in certain Derby- 
shire localities. It would be very desirable however to procure more 
specimens of both C. trigonalis, and C. EycJchoUiana, and especially 
those shoAving the interior. 
Discina. — Two species only have been retained, viz., D. nitida and 
B. Davreuxiana de Kon. ; but as of this last but a single example has 
been found by Mr. J. Wright, in the limestone of Little Island, in Ire- 
land, it is therefore here doubtfully recorded. I may also mention that 
I am strongly impressed with the idea that the Perm'an D. Koninckii 
cannot be specifically separated from the Carboniferous D. nitida. 
I/ingula. — The many so-termed species are reduced to four, viz., 
Lingula squamiformis, (which has sometimes attained upwards of one 
inch and a half in leng-th). L. wytiloides, a more elongated species, 
L. Credneri, Avhich may possibly be a variety of L. mijtiloides, and L. 
Scotica which is separable from all the others by its tapering beaks and 
peculiar external sculpture. 
Having thus briefly exposed the present state of my researches in 
connection with British Carboniferous Brachiopoda, as well as men- 
tioned some of the difficulties which still beset my mind with reference 
to the positive value of certain so-termed species, and exposed my 
ignorance as well as the absolute necessity for much further research, 
let us cast a rapid glance on the Brachiopodous life dm4ng the depo- 
sition of contemporaneous (?) Carboniferous rocks in other parts of the 
world, in order to ascertain whether our British fauna in this respect 
was not to a certain extent universally represented. In Europe we 
find that where carboniferous strata prevail a vast majority of the same 
species exist ; and as those of Belgium, France, Russia, etc., are 
already so well known, from the researches of several distinguished 
palaeontologists, we will at once proceed to India, where out of twenty- 
five or twenty-six species of Carboniferous Brachiopoda hitherto 
determined, some fourteen or fifteen were found (on an examination 
I have recently made) to be specificaly identical with British forms of 
Spirifera striata, S. lineata, S. odojjlicata, (cristata,) Atlujris Eogssii, 
A. suhtilita, Betzia radialis, Bhynchonella plcurodon, Streptorhynclms 
crenistria, Orthis resupinata, Productiis striatus, P. costatus, P. senii- 
retimlatus and P. longispinus, and a further research in these distant 
regions w4U no doubt bring to light a larger number of common 
species. 
VOL. IV. H 
