said to be found in Carboniferous Rocks. 39 
the former to be merely a variety of another Permian species 
(D. elongata) not yet admitted by him to belong to the Car- 
boniferous fauna, it being in his opinion “certainly specifi- 
cally distinct” from D. hastata—a carboniferous species. Mr 
Davidson divides Dielasma elongata into two varieties, viz., 
genuina and suflata, the latter being the species under con- 
sideration. 
Martinia Clannyana, King. 
Regarding this species, I have stated that it “ closely re- 
sembles the Devonian Aitrypa unguicula of J. de C. Sowerby, 
as figured by Professor Phillips in his ‘ Paleozoic Fossils of 
Cornwall’ (pl. xxxvii., p. 19)”—a species, the identity of 
which with Martinia Urei Mr Davidson considers as “highly 
probable (if not perfectly certain)” (vide “Scottish Carb. 
Brach.,” Geologist, vol. iii. p. 19). While preparing his 
‘“ Monograph of British Permian Brachiopoda,” Mr Davidson 
took some trouble in working out the relation of the last- 
named shell to the Permian species, and he then observed 
—“Tam still uncertain whether it is in reality distinct, or 
simply a variety or race slightly modified by time”’ (p. 16). 
In a later publication, the one referred to in the “ Geologist,” 
he expresses himself more decidedly in favour of their identity ; 
but I do not find that he has adduced any further evidence 
to support the view he has taken: on the contrary, I think if 
any point is proved, it is that Martinia Clannyana and M. 
Urei are quite distinct. 
_ Mr Davidson, wishing to have my opinion as to the rela- 
tionship of the two species, sent me several specimens of JZ. 
Urei from Carluke, for comparison with M. Clannyana from 
near Sunderland. I replied to him as follows :—*“ Urei and 
Clannyana are, | am decidedly of opinion, distinct species, 
though apparently closely allied to each other. Urei differs 
from Clannyana in being a wider shell; it has the umbone 
more incurved ; the area of the small valve not so deep; the 
small valve flatter, and more excavated, as it were, towards 
the posterio-lateral angles; the spines decidedly less nume- 
rous; and the median sulcus more pronounced in both valves.” 
The above, with a slight oversight, is inserted in Mr Davyid- 
