NEW FORMS OF MARINE DIATOMACEJ]:. 



477 



as must, indeed, be the case, since the Clyde and all its tributaries bring down 

 such forms, yet the new forms in question appear to be all of marine origin. 

 They are, in general, much too abundant to have been derived from any other 

 quarter, whereas the fresh-water forms among them are much scattered. It 

 is proper also to state, that although all these forms are, to the best of my 

 belief, new to Britain, yet a few of them have been described by Ehrenberg in 

 some of his numerous works, and also by De Brebisson. The great majority, 

 however, have not anywhere been figured ; not, at least, in any works accessible 

 to me. 



As the new forms belong to a very few genera, it will be convenient to arrange 

 them in groups. Those I shall adopt are as follow : — 



I. Naviculoid Forms. 

 II. Cocconeides. 



III. Filamentous Forms. 



IV. Discs, including Campylodisci. 



V. Amphiprorse. 



(A. Simple. 

 VI. Amphorae. { „ _ . 



IB. Complex. 



VII. Miscellaneous. 



GROUP I. 



Naviculoid Forms. 



These, as is usual in all gatherings, are numerous. Including two or three 

 varieties of species already known, those which I have recognised as new are 



the following : 



— 







1. 



Navicula minor, n. sp. 



10. Navicula spectabilis, n. sp. 



2. 





Cluthensis, n. sp. 



11. 



prsetexta, Ehr. 



3. 





inconspicua, n. sp. 



12. 



Bombus, Ehr. 



4. 





brevis, n. sp. 



13. 



Lyra, Ehr. 



5. 





Claviculus, n. sp. 



14. 



Lyra, Ehr. var. (3, abrupta. 



6. 





Musca, n. sp. 



15. 



Smithii, var. /S, fusca. 



7. 





rectangulata, n. sp. 



16. 



Smithii, var. y, nitescens. 



8. 





nebulosa, n. sp. 



17. .. 



Smithii, var. d, suborbicularis 



9. 





Barclayana, n. sp. 



18. 



maxima, Greg. 



1. Navicula minor, n. sp. PL IX., fig. 1, Form rectangular in the middle, acu- 

 minate at the ends, which are acute. Length from 0-0012" to 00025"; breadth 

 0-0004" to 0-0008". Striae fine, inclined near the ends, not reaching the median 

 line, 36 to 40 in 0001". The whole form has a delicate aspect. 



This little form, represented in fig. 1, occurs in two or three of the Loch Fine 

 dredgings, in one of which it is sufficiently frequent. 



VOL. XXI. PART IV. 6 N 



