part 2] SYRINGOTHYRIS AXD SPIRfFERINA. 183 



almost confined to the South-Western Province. It is represented 

 by fragmentary specimens recorded by Vaughan from Km in the 

 Bristol area, and reaches its acme in that district in K p and in 

 the Burrington Section and in the east of Glamorgan, in K.,. 

 Other localities are : Coed yr Gang, Upper Neath Valley, K, 1 ; 

 Mitcheldean district (Gloucestershire), K . 



Syringothyris is said to be very rare in K in Ireland. 2 

 Remarks. — The fiat area serves to distinguish this species from 

 S. cuspidata mut. cyrtorhyncha ; and its small size, and slender 

 but sharply-defined costse enable it to be distinguished from those 

 forms which occur at higher horizons. 



Stringothtkis elong-ata, sp. nov. (Text-figs. 1 e, If, SJi, & 

 Sj, pp. 166, 178; PL XII, figs. 3-5.) 



Description: — Pedicle-valve. — Area flat, and about twice 

 as wide as high, apical angle about 100°, beak sharp : sinus wide 

 and well defined, the median line along its floor slightly convex. 

 Cost* distinct, flattened and separated by narrow furrows; about 

 eighteen or twenty on each lateral slope, those nearest the sinus are 

 about 2 mm. wide at the anterior margin : lateral slopes more or 

 less flattened and falling away sharply from the plane of the area. 

 Delthyrial supporting-plates- subparallel ; transverse plates not 

 deeply submerged ; syrinx relatively large. ( See text-figs. 1 e & If) 



Brachial valve more than twice as wide as long, cardinal 

 extremities subangular or slightly produced : costae as in the 

 opposite valve, but more clearly defined : fold wide and depressed, 

 but distinctly raised above the general level of the valve. 



The dimensions of an average specimen are as follows: — width 

 along hinge-line, 66 mm. ; length of brachial valve, 24 mm. ; 

 height of area, 28 mm. 



Remarks. — This species resembles in general appearance 

 S. principalis from the Oleistopora Zone, but differs from it in 

 its size, and in the small angle of divergence of its delthyrial 

 supporting-plates, which are relatively longer, and extend completely 

 across the cavity in sections where the syrinx has nearly disappeared, 

 while in S. principalis they are already incomplete in sections 

 where the syrinx is best developed. From >S. cuspidata it differs 

 in its greater relative width, larger apical angle, and its subangular 

 cardinal extremities. 



Holotype. — A specimen in the collection of the Geological 

 Survey of Ireland (Reg. No. 1192 ) ; horizon, Ganinia Zone ; 

 locality, south of Adare (Limerick). (PL XII, figs. 4«-lc.) 



Horizons and local it ie s. — This species is represented in rocks 

 of both Lower and Upper Avonian age ; and, Avhile examples from 

 different horizons present small variations, they are similar in 

 general characters, nor can they at present be satisfactorily differ- 

 entiated. It is recorded from Z to C in Ireland : for instance, 



1 Collected by the late Mr. C. H. Cunnington. 

 - Doug-las [8] p. 54S. 



Q.J.G.S. No. 302. . o 



