576 MR. J. A. DOUGLAS ON THE [Nov. 1909, 



which are comparable with this species, mention must he made of 

 the mutation of Spirifer clathratus figured by Dr. Yaughan. 1 This 

 author considers that >Sp. Tconincki is a late mutation of one of the 

 clathratus group. 



The form figured by Davidson on pi. iv, fig. 14, of his ' British 

 Fossil Brachiopoda' as Spirifer rnosquensis from Little Island 

 (Ireland) occurs at an horizon far below that of the Russian 

 shell ; and, since the strong dental plates, diagnostic of that 

 species and its allies which are grouped under the generic name 

 Choristites, have never been determined in his specimens, it 

 appears likely that they are related to the species now described, 

 which (though it does not possess large dental plates) has somewhat 

 the outward appearance of a Choristites. 



Spirifer sttbctnctus, de Kon. 



Specimens which occur commonly in the Syringothyris Zone 

 agree closely with the form described and figured by L. GK 

 de Koninck from the Waulsortian of Belgium. 2 



(B) Corals. 

 Michelinia. 



MlCHELINIA GRANDIS, M'Coy. 



' British Palaeozoic Fossils ' 1855, p. 81 & pi. iii C, figs. 1-1 a ; and Ann. & 

 Mag. Nat. Hist. ser. 2, vol. iii (1849) p. 123. 



I have examined M'Coy's type-specimen, preserved in the 

 Sedgwick Museum at Cambridge, and have no hesitation in 

 assigning the form common at the base of S x in County Clare to- 

 this species. 



Zaphrentis. 



Zaphrentis omaltusi, M.-Edw. & H. (var. densa, Carruthers)* 

 (PI. XXVII, fig. 9.) 



As interpreted by Mr. R. G. Carruthers, Greol. Mag. dec. 5, vol. v (1908) 

 p. 25 & pi. iv, fig. 7. 



A densiphylloid Zaphrentis, which Mr. Carruthers refers to the 

 above species and variety, occurs in some abundance in Z t of 

 County Clare. Nearly every specimen collected was found to be 

 silicified, and the structure thereby almost completely obscured ;. 

 the figured specimen, however, shows the radial disposition of the 

 septa and the fusion of their inner ends. 



Zaphrentis konincki, M.-Edw. & H. 



As interpreted by Mr. R. Gr. Carruthers, op. cit. p. 67 & pi. v, figs. 1-4. 

 This species occurs in great abundance throughout Z o5 reaching 1 

 its maximum at horizon y. Forma a of Carruthers is the type 

 usually met with. 



1 Proc. Bristol Nat. Soc. n. s. vol. x (1902-1903) pi. ii, fig. 3. 



2 Ann. Mus. Roy. Hist. Nat. Belg. vol. xiv (1887) pi. xxiv, figs. 4 & 5. 



