152 T. Davidson — Upper Silurian Brachiopoda. 



underlying the limestone. I have much pleasure in naming it 

 after the Kev. H. G. Day. 



10. Orthis elegantulina, n. sp. PI. V. Fig. 12. 



Shell small, nearl}' circular, and about as broad as long. Dorsal 

 valve moderately convex, divided longitudinally by a sinus of 

 greater or lesser depth. Hinge area narrow. Ventral valve deeper, 

 and more convex than the dorsal one, and slightly longitudinally 

 keeled. Hinge-line shorter than the breadth of shell, beak small, 

 incurved, area triangular, fissure small. Surface of both valves 

 marked by strong raised stria3, bifurcating once or twice as they 

 near the lateral and frontal portions of the valves. Length 3, 

 width 3, depth 2 lines. 



Obs. — My attention was first drawn to this small species at the 

 commencement of 1880 by Mr. J. F. Walker. It is a much smaller 

 shell than Orthis elegantula, and more circular, its beak much less 

 incurved and of smaller proportions, and its ribbing or striation 

 comparatively much stronger than in 0. elegantula. 



0. elegantulina swarms in the Lower Wenlock Shales of Build was 

 in Shropshire, and is less abundant in the Upper Wenlock Shales. 



11. Eichioaldia Capeicelli, Dav. sp., Sil. Mon. p. 193, pi. xxv. 



figs. 12, 15. 



Ever since I first described this beautifully sculptured shell in 

 1848, I have felt uncertain whether it was provided with spiral 

 appendages. I consequently placed in the hands of Mr. Glass 

 a number of well-preserved specimens filled with spar, and which 

 had been obtained by Mr. Maw from his washing of Buildwas 

 Lower Wenlock Shales. After many experiments not the trace of 

 a spiral coil could be detected, and Mr. Glass arrived at the con- 

 clusion that it had none. 



Prof. J. Hall having kindly sent me several well-preserved 

 specimens of his Eichivaldia reticulata, I am convinced that it is the 

 same species as my E. CapeiveUi. At page 170 of the Twenty- 

 Eighth Eeport of the New York State Museum of Natural History, 

 Prof. Hall says, " Surface of the shell, except a small place on the 

 umbo of the ventral valve, covered by fine reticulate markings with 

 elongate, generally hexagonal pits or openings, with thin and sharp 

 ridges within ; these markings vary in different specimens, and also 

 in diiFerent parts of the same individual, being generally finest on 

 the cardinal slopes. The small triangular space near the ventral 

 beak which is destitute of marking has the appearance of having 

 been exfoliated ; but since this is an invariable character in all the 

 individuals examined, varying in size with the size of the shell, 

 it is probably dependent upon organic causes." This description of 

 the shell sculpture, and of the smooth part at the umbo of the ventral 

 valve, is exactly what we find, not only in our British specimens, 

 but also in Swedish ones ; and in pi. 2, fig. 16, of his " Fi-agmenta 

 Silurica," Prof. Lindstrom gives a good illustration of this 

 peculiarity. 



