18 F. KITTON ON SOME NEW DIATOMACE^. 



the central elevation, furrows distinct, pnncta moniliform,* radiant 

 between the margin and elevations, upon which they are more dis- 

 tant and less regularly radiant. Diameter, '0029" to 62". PI. IV. 

 Fig. 1. The number of processes varies from 3 to 5. 



The most conspicuous feature of this species is the flat, elevated 

 centre, aptly compared by a correspondent to a miniature fort, the 

 projecting processes resembling the guns. 



Podosira maxima, Kiitz., var. ? Valve hyaline, and the punc- 

 tate strias more distant than in the type species. 



P. maxima, abnormal. This remarkable monstrosity cannot be 

 clearly understood excepting by reference to the drawing. The ir- 

 regular configuration, apparently upon the valve, is really below it, 

 and is probably a malformed internal valve. The specimen is a frus- 

 tule, of which the upper valve appears to be normal, and shows con- 

 spicuously the irregular " black spots " which Herr Grunow, in his 

 paper on the " Caspian Sea Diatoms" (" J. R. M. S.," Vol. ii. p. 

 689), says mostly mark the beginning of new rays of puncta, but 

 from some observations I have recently made on styrax mounted 

 specimens this does not appear to be the case, an examination under 

 a binocular and a power of 400 diameters, illuminating with a 

 paraboloid, showed the black spots to be trumpet-shaped tubuli 

 extending in a direction more or less perpendicular to the upper and 

 under surfaces of the valve, but apparently imperforate, as the 

 styrax has not penetrated them, sometimes they appeared to be 

 composed of elongated vacuoles like air-bubbles rising through a 

 viscous medium, and which had become suddenly arrested. 



The trumpet- shaped tubuli are not unlike those seen in a section 

 of Waldheimia australis, or the pseudopodal apertures in Globi- 

 gerina, &c. PI. IV., Fig. 2, frustule. Fig. 3, diagrammatic section 

 of valve. 



Amphipleura pellucida, var. rectus, F. K. Valve linear, margins 

 parallel up to the commencement of the furcate ends of the raphe, 

 when the valve becomes lanceolate. Length, -009 ; breadth, 

 •00075 ; strire punctate, 65 in -00K PI. IV., Fig. 4. Rare. 



* Mr. E. M. Nelson has called my attention to the markings between the 

 headings, which give a granular or shagreen-like appearance to the surface 

 of the valve, similar to that on A., formosus, in the immature valves of 

 the latter species they appear as distinct punctae, hut as the valve increases 

 in thickness they become less apparent. He also informs me that the Aula- 

 codiscus Havtianvs shewn by him at the meeting held Feb. 8, LS84- (vide 

 Journ., Vol. i, S. 2, p. 371), was the above, Hartianua being a misprint. 



