NEW FORMS OF MARINE DIATOMACES. 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 Bresisson. 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. 
IlIJ. Filamentous Forms. 
IV. Discs, including Campylodisci. 
V. Amphiproree. 
(A. Simple. 
VI. Amphoree. ii: Gone” 
VII. Miscellaneous. 
GROUP I. 
Navicutor 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. ...  pretexta, Ehr, 
3. inconspicua, n. sp. 12. ..._ Bombus, Ehr. 
4, brevis, n. sp. 13. ... Lyra, Ehr., 
5. Claviculus, n. sp. 14, ... ° Lyra, Ehr. var. 8, abrupta. 
6. Musca, n. sp. 15, ...  Smithii, var. 6, fusca. 
7. rectangulata, n. sp, 16. .... Smithii, var. y, nitescens. 
8. nebulosa, n, sp. 17. .... ‘ Smithii, var. 6, suborbicularis, 
9. Barclayana, n. sp. 18. ... . maxima, Greg. 
1. Navicula minor, n. sp. Pl. 1X., fig.1. Form rectangular in the middle, acu- 
- minate at the ends, which are acute. Length from 0:0012” to 0:0025”"; breadth 
— 0°0004" to 0:0008”. Strize fine, inclined near the ends, not reaching the median 
line, 36 to 40 in 0-001”. The whole form has a delicate aspect. 
i 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. 6N 
