538 



PROFESSOR GREGORY ON 



lata (JEhrenb., I. c, tab. xix., fig. 13) which is represented with three terminal 

 teeth ; but these teeth can scarcely be the remains of a corona, as Kutzing, in de- 

 fining the frustule, says, "utroque fine medio apiculis elongatis hispido." Upon 

 the whole, the safe course seems to be to regard the subject of this notice as not 

 only specifically but generally new ; and I gladly adopt the suggestion of Pro- 

 fessor Walker- Arnott, that it receive the name of Creswellia in honour of its dis- 

 coverer, the Rev. R. Creswell, a gentleman well known to Algaeologists, and to 

 whom Professor Harvey has already dedicated a new British Schizothrise. The 

 following character will distinguish it at once from all its allies. 



Creswellia. Frustules cylindrical, two-valved, cohering by short, filiform pro- 

 cesses into a continuous filament. Valves cup-like, cellulate, destitute of any si- 

 liceous connecting band. PI. XIV., fig. 109. 



This singularly interesting Diatom, which may be called Creswellia Turris, 

 has only been found in the locality already mentioned by Mr Creswell, and off 

 the Island of Curnbrse, where it was dredged along with the nests of Lima hians 

 by Mr Hennedy, and a single frustule detected by Dr Walker-Arnott. 



The figure represents four frustules, the largest number which has been 

 hitherto observed in connection. It will be perceived that in two of the frustules 

 one of the valves is dark, and more or less opaque. This appearance we are quite 

 unable to account for. It sometimes happens that the whole frustule is dark. 

 Generally they are all beautifully clear. The structure is highly cellulate, the cells 

 hexagonal. The length of the frustule is about -0028"; the breadth about •0016". 



Fig. 







EXPLANATION OF PLATE IX. 



1. 



Navicula 



minor, n. sp. 



Fig. 16. Navicula Smithii, var. y, nitescens. 



2. 



... 



Cluthensis, n. sp. 



— 17. ••• Smithii, var. 8, suborbicularis. 



3. 





inconspicua, n. sp. 



— 18 & 18 b, maxima, Greg., S.V. and F.V. 



4. 



... ' 



brevis, n. sp. 



— 19. Pinnularia subtilis, n. sp. 



5. 





Claviculus, n. sp., S.V. x 800. 



— 20. ... rostellata, n. sp. 







5 b, do., F.V. x 800. 5 c, do. 



— 21. ... Allmaniana, n. sp. 







S.V. x 400. 



— 22. ... Pandura, Breb., var. /?. elongata. 



6. 



... 



Musca, n. sp. 



— 23. Cocconeis distans, Greg. 



7. 





rectangulata, n. sp. 



— 24. ... ornata, n. sp. 



8. 





nebulosa, n. sp. 



■ — 25. ... dirupta, n. sp. 



9. 



... 



Barclayana, n. sp. 



— 26. ... nitida, n. sp. 



10. 



... 



spectabilis, n. sp. 



— 27. ... pseudomarginata, n. sp. 



11. 





praetexta, Ehr. 



— 28. ... major, n. sp. 



12. 



... 



Bombus, Ehr. 



— 29. ... splendida, n. sp. 



13 & 13 b, 



Lyra, Ehr. 



All the above, except figs. 5 and 5 b, are magnified 



14 & 14 b, 



Lvra, var. ft. 



400 diameters. 



15. 



... 



Smithii, var. /?, fusca. 





Fig. 30. Denticula (?) interrupta, n. sp. 



— 31. ... (?) capitata, n. sp. 



— 32. ... (?) ornata, n. sp. 



— 33, 33 b, & \ . . , 



33 c, j-( ? ) l£EVls - 



EXPLANATION OF PLATE X. 



Fig. 34. Denticula nana, n. sp., F.V. 34 b ; do. S.V. 

 35b, 

 35 c, 



- 35, 35 b, & J m . norj n> gpj F y 35 d . do> sv; 



■ 36. ... distans, n. sp., F.V. 36 b ; do. S.V. . 

 — 37 & 37 b, . . . staurophora, n. sp., F.V. 37 c ; do.S.V 



