434 Mr. C. Mereschkowsky on Stauronella. 
speaking of such forms, says :—‘‘ Je n’ai jamais vu de grandes 
formes de cette espéce, signalée surtout dans l’Océan (Atlantic) 
et les mers arctiques, les petites formes telles que celles que 
jai dessinées sont peut-étre spéciales aux mers chaudes ” *. 
The locality of var. major would be, according to Cleve :— 
Davis Strait; North Sea. 
Another variety seems to be the form figured in A. Schmidt’s 
‘ Atlas,’ pl. xxvi. fig. 35. Valve linear, with cuneate, sub- 
acute ends, not constricted in the middle; stauros narrow, 
not reaching the margins. Girdle-face unknown. The 
girdle-face represented by fig. 86 is no doubt an Amphora 
(a form of A. levis or A. ostrearta), and certainly has nothing 
to do with fig. 35. This variety, of unknown origin, may 
be named var. cuneata. 
4th July, 1901. 
EXPLANATION OF PLATE VIII. 
[All firures are magnified 1260 times. | 
Fig. 1. Stauronella constricta (Ehr.), Mer. A typical girdle-face. 
Fig. 2. Ditto. A typical valve belonging to the same individual. 
Fig. 3. Ditto. A double frustule. 
Figs. 4,5. Ditto. Both figures refer to the same individual. 
Fig. 6. Ditto. One of the smallest individuals observed. 
Fig. 7. Stauronella constricta, var. linearis, Mer. First type of valves 
(see also fig. 11). 
Fig. 8. Ditto. A typical girdle-face, same individual as fig. 7. 
Fg. 9. Ditto. Girdle-face belonging to the valve fig. 10. 
4g. 10. Ditto. Second type of valves, perfectly linear (see also fig. 17). 
Fig. 11. Ditto. First type of valves (see also fig. 7). 
Figs. 12-15. Ditto. Small individuals. 
Figs. 16, 17. Ditto. Endochrome in the valvular aspect ; pr., pr., pyre- 
noids. 
Fig. 18. Ditto. Endochrome in the zonal aspect. 
4g. 19. Ditto. Diagram representing an ideal transverse section of a 
frustule along the line a 6 in figs. 17 and 18, and showing 
the disposition of the chromatophores; the dentitions on the 
zone-faces indicate the longitudinal divisions of the zone; 
pr., pyrenoid. 
All figures represent individuals from the Black Sea. 
* Peragallo, Diat. mar. d. Fr. p. 57. 
