1863.] DAVIDSON — NOVA-SCOTIAN BRACHIOPODA. 173 



twelve or thirteen small radiating* ribs, of which fonr or five occupy 

 the surface of the fold. The sinus in the ventral valve is of moderate 

 depth, and the surface is ornamented as in the dorsal valve. The 

 beak is gently incurved, and exhibits a small circular foramen under 

 its angular extremity. Length 5 lines, width 5 lines, depth 3 lines. 



Of this shell I have seen but two specimens, which I detached 

 from a lump of the Brookfield shell-limestone, and of which one ex- 

 hibited the two curved internal lamellae characteristic of the genus 

 Rhynchonella. It is quite distinct from young shells of Rhynchonella 

 jmgnus and R. pleurodon. In the last-named species the ribs that 

 adorn the lateral portions of the dorsal valve are very much curved, 

 while those of the ventral are nearly straight, with their extremities 

 bent upwards ; in addition to which, the ribs begin to be longi- 

 tudinally grooved along their median portion at some distance from 

 the margin. None of these characters are observable in the small 

 Rhynchonella under description. 



9. Rhynchonella, sp. PI. IX. fig. 17. 



Upon some fragments of Lower Carboniferous limestone brought 

 from Nova Scotia by Sir C. Lyell are several imperfect, undeter- 

 minable valves of a Rhynchonella which differs from the preceding- 

 species by its size, as well as by the number of its small radiating 

 ribs. Of these last I have counted as many as thirty -five or forty 

 upon each valve. In size it appears to have measured about 7 or 8 

 lines in length by 9 in width. I abstain from proposing for it a spe- 

 cific denomination, as the material is so imperfect. The specimen 

 belongs to the Geological Society. 



In fig. 15 is represented another Rhynchonella, also undeterminable. 



10. Rhynchonella pugnijs ?, Martin, sp., Petrif. Derb. tab. 22. 



figs. 4, 5, 1809. 



Two or three very small specimens, received from Dr. Dawson 

 after my plate had been completed, much resemble certain young 

 shells of Martin's species ; they are derived from the Lower Carbo- 

 niferous limestone of Windsor and East River. 



11. Strophomena analoga, Phillips. PI. IX. fig. 18. 



Producta analoga, Phillips, Geol. Yorksh. vol. ii. pl. 7. fig. 10, 

 1836. 



Upon a specimen of dark, impure limestone brought from Nova 

 Scotia by Sir C. Lyell, and now in the Society's Museum, I found 

 a well-characterized example of this species, which, in Sir C. Lyell's 

 list, had been confounded with Productus Martini. 



12. Streptorhynchtts crenistria, Phillips. PI. IX. fig. 19. 



Several crushed valves, referable to this species, occur on a speci- 

 men of Carboniferous shale from Shubenacadie, for which I am 

 indebted to Dr. Dawson. These valves exactly resemble certain 

 small specimens found in several British Carboniferous shales. Then- 

 surfaces are covered with numerous radiating raised stria?, with a 



