334 ME. E. S. C0BB0L1) ON THE [vol. lxxvi, 



A comparison may be made with M. (P.) logani Walcott, 1 

 which has a wide, open delthyrium and a small ' shelf -like ' pseudo- 

 deltidium, hut differs in form from the Comley fossil. 



M. (P.) sluarti Walcott 3 has an open delthyrium, but differs 

 in outline and convexity from M. (P.) minor. 



The Comley form has the same general outline as M. (P.) undosa 

 Mobergy 3 from drift blocks of Lower Cambrian Sandstone of 

 Oland, but is much smaller, and the false areas cannot be compared, 

 as the Swedish specimens are defective. 



MlCEOMITEA MINOR, Vai\ GIBBOSA 110V. (PI. XXI, fig 17.) 



A specimen in the collection made by Mr. Rhodes [RR 1117], 

 and another in the British Association collection [2178] differ 

 from those described above in having the anterior slope much more 

 strongly convex ; this gives a gibbous aspect to the shell. 



Mr. Rhodes's specimen was obtained from the Olenellus Lime- 

 stone of Comley Quarry ; the exact horizon of the other specimen 

 is, however, doubtful. 



Localities and horizon. — Comley, Lower Cambrian; from 

 the Olenellus Limestone of the Quarry, horizon Ac 2 . Also from 

 the same horizon in the Cwms, about 2 miles south of Comley 

 Quarry. 



Miceomitea (?) sp. indet. (PL XXI, fig. 26.) 



Associated with M. (P.) pJiillipsi and Walcottina two valves 

 have been found, which were thought to be dorsal valves of 

 W. lapworthi (see below, p. 336), and were figured for description. 

 One of the figures is reproduced in PI. XXI. There is a strong 

 superficial resemblance to the figures given by Walcott 4 of the 

 dorsal valve of Kutorgina graniilata Matthew, but the shells do 

 not agree with the description. The umbo is not ' depressed to 

 the cardinal line,' it stands up almost vertically, and there is no 

 sign of ' a median septum.' 



In the specimen figured the posterior portion is imperfect, but 

 suggests a similarity to the false area of the ventral valves of 

 31. (P.) phillipsi and its congeners. 



Dimensions in millimetres. — Length=9; width = 12 ; 

 height = 1 or more. 



Locality and horizon. — Comley, Lower Cambrian ; from the 

 Cwms sub-area, horizon Ab r 



Walcottina, gen. nov. 



Two species of brachiopoda from the lowest fossiliferous horizon 

 known in the Comley district appear to be intermediate between 



1 1912, pi. ii, figs. 6, 6 a & 6 b. 



2 Ibid. p. 354 & text-figs. A, A', A", B, B'. 

 :i 1892, p. 112 & pi. iii, figs. 10-12. 



4 1912, pi. v, figs. 5 b & 5 c. 



