952 DK P. R. C. REED ON THE 



of a median rib instead of a groove on the pedicle-valve, and of a single rib in the 

 sinus of the opposite valve. If the material was better it would deserve a separate 

 specific designation. There are some coarser-ribbed forms, probably of the same or 

 an allied species, which have only 6-7 ribs on each side of the brachial valve and the 

 ribs are more angular, more prominent, and wider apart. 



Rhynchospira (Homceospira) camreganensis, sp. nov. 

 (Plate XXIV, figs. 47-49.) 



1 1883. Rhynchonella auneata (Dalman), Davidson (pars), Mon. Brit. Foss. Brack., vol. v, Silur. Snppl., 

 p. 152 (non Rhynchonella cuneata, Dalman, sens. str.). 



Shell oval, longer than wide, widest across middle, unequally biconvex. Pedicle- 

 valve convex, subcarinate, with sloping shoulders inclined at about 30°-45° and 

 extending to middle of shell ; beak high, pointed, slightly incurved. Brachial valve 

 subcircular, less convex and shorter than pedicle-valve, with very weak median depres- 

 sion ; beak small, not pointed ; interior with median septum extending about one-third 

 the length of the valve. Surface of valves covered with 27-31 small low rounded 

 closely placed ribs of equal size, except median one on pedicle-valve, which is slightly 

 larger ; lateral ribs on brachial valve curve gently outwards near anterior end. 



Dimensions. — Length, 7'0 mm. ; width, 5 '5 mm. 



Horizon. — Camregan Group. 



Locality. — Camregan Wood. 



Remarks. — This small shell, which was labelled in Mrs Gray's collection 

 Rhynchonella cuneata, resembles Rhynchospira Bouchardi, var. mullochensis, but 

 has more numerous ribs and is more oval in shape. It may be compared with 

 Rh. (Homceospira) evax (Hall),* of the Niagara Group, of which some of the examples 

 have finer and more numerous ribs than others. 



Genus Nucleospira, Hall. 

 Nucleospira pisum (Sowerby) ? 



1839. Spiriferl pisum, Sowerby, in Murchison's Silurian System, p. 630, pi. xiii, fig. 9. 



1866. Nucleospira pisum (Sowerby), Davidson, Mon. Brit. Foss. Brack., vol. iii, pt. vii, p. 106, pi. x, 



figs. 16-20. 

 1883. Nucleospira pisum (Sowerby), Davidson, op. cit., vol. v, Silur. Suppl., pp. 91, 224, pi. iv, 



figs. 15-18. 



Two internal casts of brachial valves in Mrs Gray's collection may probably be 

 referred to this species, but the evidence for its occurrence is poor. As Davidson 

 remarked, it can scarcely be specifically distinguished from N. pisiformis, Hall, of 

 the Niagara Group. 



Horizon. — Camregan Group. 



Locality. — Bargany Pond Burn. 



* Hall, 28th Rep. New York State Mus. Nat. Hist, 1879, p. 160, pi. 25, figs. 13-21. 



