DAVIDSON — ON SOME FOSSIL BRACHIOPODA. 
467 
mucb resemblance to the one and to the other, but I have 
deemed it preferable, for several reasons, to retain it, at 
least provisionally, as a separate species. It will be 
desirable to assemble a greater number of specimens 
than I have been able to command, in order to determine 
the true character of this species. 
PLANATA, Phillips, Geol. of York. pi. x., fig. 3, 1836 : and Dav., 
pi. vii., fig. 25 — 30. This appears to be a good species, 
and easily distinguishable. 
FusiFOKMis, Phillips, pi ix., fig. 10, 11 ; Dav., pi. xiii., fig. 15. Of 
this only a single imperfect specimen appears to have 
been discovered (now in the British Museum), so that 
the character and value of the species cannot be con- 
sidered as finally established j search for more examples 
is very desirable. 
TEiANGULAKis, Martin, sp , Pet. Derb., pi. xxxvi,, fig. 2, 1809: 
and Dav., pi. v,, fig. IG — 24 = ornithorlnjncha, M'Coy. 
TRiGONALis, Martin, sp.. Pet Derb., tab. xxxvi., fig. 1, 1809: 
and Dav., pi. v., fig. 25 - 34. 
BisuLCATA, Sow., M.C., tab. ccccxciv., fig. 1, 2, 1825: and Dav., 
pi. v., fig. 1 : pi. vi , fig. 1 — 19 : and pi., vii., fig. 4 = 
semicircularis, Phillips = cakarala, M'Coy = traiisiens, 
M Coy. ? 
CONVOLUTA, Phillips, Geol. of York., pi. ix., fig. 7,1836. and 
Dav., pi. v., figs. 2 — 15= (?) rhomhoidca, Phillips. I 
have still some misgivings relative to this species and 
its supposed synonym ; but three or four true examples 
of the typical S. coiwoluta have come tinder my obser- 
vation, and it will be very desii-able for us to ascertain 
whether Phillips' species may not be a very transverse 
or exceptional condition of Sjj. bisitlcata, Sow. 
GEANDicoSTATA, M'Coy, Brit. Pal. Foss., pi. iii., d., fig. 29, 1855 : 
and Dav., pi. v., fig. 38, 39, and pi. vii., fig. 7-16. 
N.B. — All these forms appear to be nearly related. 
LAMiNOSA, M'Coy, Synopsis Carb. Foss. of Ireland, pi. xxi., fig. 
4, 1844 : and Dav., pi. vii., fig. 17 — 22 = tricornis, De 
Koninck. This appears to be a very good species, but Is 
rarely found in good condition in our English or Lish 
localities. 
cuspiDATA, Martin, sp., Trans. Liu. Soc, pi. iii , figs., 1 — 6, 1796 : 
and Dav., pi. viii., 19 — 24: pi. ix., figs. 1, 2 = simplex, 
M'Coy, not of Phillips. 
DisTANS, Sow., M.C., tab. 494, fig. 3, 1825 : and Dav., pi. viii., 
fig. 1 — 17. I have never met with any example in which 
the dcltidium was completely preserved, but from the 
inspection of an internal cast from the dolomitic carbo- 
niferous limestone of Breedon it would appear that Sp. 
cKspidala possessed a circular foramen in its deltidium, 
as in Dalman's Cyrtia, to which these two species pro- 
bably belong. 
MEsoGONiA, M'Coy, Synopsis, pi. xxii., fig. 13, 1844 : and Dav., pi. 
vii., fig. 24. This is said by Prof, de Koninck to be a 
good species, but I have never had an opportunity of 
studying the shell. 
N.B. — Sp. hicarinata, M'Coy, Synopsis, pi. xxii., fig. 10 : 
Sp. dccemcoslata, M'Coy, fig. 9, and Sp. siib-conicus, Martin, 
Pet. Derb., tab. xlvii., fig. 6-8, 1809, are very doubtful 
species, and cannot be accepted without further research. 
