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



Spirifer. 



Spiriper attentjatus, Sow. (PI. XXVI, fig. 7.) 



The opinion that this shell was only a variety of Spirifer striatus 

 was held by de Verneuil, M'Coy, Davidson, and for a long time 

 by de Koninck. The last-mentioned author, however, has since 

 published a description of Spirifer attenuaius as a separate species, 

 and has brought forward abundant evidence to justify the dis- 

 tinction. This shell, which is characteristic of the Waulsortian 

 Phase of Belgium, occurs also in great numbers in the Syringothyris 

 Zone of County Clare. The specimen that I have figured was 

 selected to show the nature of the ribbing, but the posterior lateral 

 extremities, which are always angular, are unfortunately broken. 

 De Koninck s figures are somewhat poor, and the best example is 

 to be found on pi. ii, fig. 13 of Davidson's ' Monograph of British 

 Fossil Brachiopoda ' vol. ii (1857-63). 



The following is L. G. de Koninck's description of this species 

 (Ann. Mus. Boy. Hist. Nat. Belg. vol. xiv, 1887, p. 115):— 



' Shell transverse, much broader than long, of a subsemicircular form with 

 angular lateral extremities ; valves of nearly equal depth. The median fold of 

 the dorsal valve is fairly broad at its anterior border, but is very little elevated 

 and evenly rounded. The sinus of the ventral valve is fairly deep, and 

 bounded on each side by a radial rib, a little more strongly marked than the 

 adjacent ones The surface of each valve is covered by narrow ribs sepa- 

 rated by grooves of equal width and fairly deep. The ribs, which are the 

 same on the fold and sinus as on the rest of the shell, bifurcate several times, 

 and thus preserve almost their initial width throughout their length. The 

 first bifurcation takes place at a short distance from the beaks, and the ribs 

 sometimes collect into bundles which divide the surface into several small, 



more or less isolated lobes The ribs are smooth for the greater part of 



their length, and are only interrupted by transverse lines of growth, often at 

 unequal distances, near the margin of the shell.' 



The figured specimen shows three well-marked bundles on the 

 dorsal fold, which have their origin in three primary ribs. 



This species differs from Spirifer striatus, chiefly by its smaller 

 size, and by the fineness and regularity of its ribs and the charac- 

 teristic grouping into bundles. 



Spirifer aff. cxaihrattjs, M'Coy & Vaughan; (PI. XXVI, fig. 6.) 



As interpreted by Dr. A. Vaughan, Proc. Bristol Nat. Soc. n. s. vol. x 

 (1902-1903) pp. 125-27, and Quart. Journ. Geol. Soc. vol. lxi (1905) 

 p. 300 & pi. xxvi, fig. 5. 



This species is abundant throughout the Zaphrentis Zone in 

 County Clare ; it continues into the Syringothyris Zone, from 

 which the figured specimen was derived. 



Spiriper konincki, sp. nov. (PI. XXVI, figs. 1 a & 1 b.) 



Description. — The young shell is nearly circular in outline, 

 but becomes transversely oval with increased growth. Area rather 

 broad, concave, with subparallel sides ; cardinal angles rounded. 

 Beaks prominent, incurved over the large triangular delthyrium. 



