294 Proceedings of the Boycd Physical Society. 



124. Paradoxostoma orcadense, G. S. Brady and D. Eobertson. 



1872. Paradoxostoma orcadense, B. and K,., Ann. and Mag. Nat. 

 Hist. (4), vol. ix. p. 53, pi. i. figs. 5-7. 



Hah. — Off St Monans ; rare. 



125. Paradoxostoma Hodgei, G. S. Brady. 



1870. Paradoxostoma Eodgei, Brady, Nat. Hist. Trans. Northumb. 

 and Diirh., vol. iii. p. 371, pi. xii. figs. 12, 13. 



Hab. — Off St Monans, frequent ; also near Fidra. 



126. Paradoxostoma flexuosum, G. S. Brady. 



1868. Bythocythere (?) flexuosa, Brady, Brit. Assoc. Report (1866), 

 p. 211. 



1889. Paradoxostoma flexuosum, B. and N., I. c, Part I. p. 236, 



pi. xxi. figs. 11, 12. 



Rah. — Firth of Forth (Brady and Eobertson). Off Bo'ness, 

 South Bay, and other parts of the estuary; frequent. 



127. Paradoxostoma affine, T. Scott. 



1890. Paradoxstoma afline, T. Scott, Eighth Rept. F. B. S., pt. iii. 



p. 325, pi. xii, figs. 8, 9. 

 1896. ,, ,, B. and N., I. c, Part II. (Appendix) 



p. 739, pi. ixiii. figs. 10, 11. 



Hah. — Off St Monans ; not common. The species which this 

 form most closely resembles is the Paradoxostoma arcuatum 

 of G. S. Brady, but it is not so narrow posteriorly, and its 

 greatest breadth is nearer the posterior extremity. It has also 

 been taken by Canon Norman near Inveraray, Loch Fyne. 



Genus (37) Machserina, Brady and Norman, 1889. 

 128. Machcerina tenuissimct (Norman). 



1869. Bythocythere tenuissima, Norman, Brit. Assoc. Rept, for 1868, 

 p. 294. 



Hah. — Dredged in deep water west of May Island; not 

 common. Also observed in the stomach of a Five-bearded 

 Eockling captured in the Forth on 13th May 1901. This 

 species is remarkably compressed, and though moderately 

 high in the middle, both ends taper gradually to a narrow 

 point, imparting to the shell a very slender appearance. 



