On the Palceozoic Bivalved Entomostraca. 403 



XXXVI. — Notes on the Palceozoic Bivalved Entomostraca. — 

 No. XXI. On some Silurian Genera and Species '^ . By 

 Prof. T. Rupert Jones, F.R.S., and Dr. H. B. Holl, 

 F.G.S. 



[Plates Xm. & XlV.t] 



Contents. 



Strejnila, gen. uov., p. 403. 10. Primitiu paucipunctata, J. & 



1. Strepiila concentnca, sp. nov., H., p. 409. 



p. 404. 11. humilis, sp, nov., p. 409. 



2. irreyularis, sp. uov., 12. valida, sp. nov., p. 409, 



p. 404. 12*. , vaa". breviata, nov., 



3. beyrichioides, sp. uov., p. 410. 



p. 405. 12**. , var. angustata, 



4. Bollia Vinei, sp. uov., p. 406. uov., p. 410. 



4*. , var. mitis, nov,, 13. tersa, J. & H., p. 410. 



p. 406. 14, umbilicata, J. & H., 



Placentula, gen. nov., p. 407. p, 410. 



5. Placentula excavata, J, & H., 15. cristata, J, et H., p. 411. 



p. 407. 16, ornata, sp. nov,, p. 411. 



6. Primitia lenticularis, J, & H,, 17. cornuta, sp. nov,, p. 411. 



p, 408. 18. eeqitalis, sp. nov., p. 412. 



7. Rcemeriana, J. & H,, 19. diversa, sp, nov,, p, 412. 



p. 408, 20. seminulmn, Joues, p. 413. 



8. fabtdina, sp. nov,, p. 408. 21, ftircata, sp, uov,, p, 413. 



9. variolata, J. & H,, p. 408. 



In our continued examination of the numerous interesting 

 specimens in the collections made by Messrs. J. Smith and 

 G. H. Vine we find the following genera and species. The 

 same numbers for the various assortments of Wenlock 

 Shales in Mr. Vine's collection are used as in the Ann. & 

 Mag. Nat. Hist., April 1886, namely : — " Shales over the 

 Wenlock Limestone, nos. 24 and 46. Upper Wenlock 

 Shales, nos. 26, 25*, 41, and 42 : Tick wood Beds. Middle 

 Wenlock Shales, no. 43 : Goalbrook-Uale Beds. Lower Wen- 

 lock Shales, nos. 22, m, 37, 38, 40 : Buildwas Beds." 



Strepula, gen. nov. 



Certain specimens, namely PI. XIII. figs. 1, 4, 6, 7, 8, and 

 9, were at first looked upon as belonging to Kirkhya, to some 

 forms of which genus (for example fig. 19, pi. iii. Ann. & 



* For No, XX, see Ann. & Mag. Nat, Hist, for April 1886, p, 337. 

 t These Plates have been drawn with the aid of a grant from the 

 Royal Society for the illustration of Fossil Entomostraca, 



