2 SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. I46 



Although it is not a particularly diminutive form in general dimen- 

 sions, it is one of the most delicate ones I have had occasion to study. 

 I have given it the name suhhyalina to indicate its extremely tenuous 

 and gossamer character. 



ACHNANTHES SUBHYALINA Conger, sp. nov. 



Plantae unicellulares ; valvae breves breviter oblongae vel lineari- 

 oblongae, interdum paullo apice constrictis, 5-10/t longae, 3-4/* latae, 

 apice late rotundatae ; valva superior cum pseudoraphe angustissima, 

 recta, mediam valvae occupante, cum linea mediana transversa angus- 

 tissima, nodulis terminalibus et nodulo centrali indeterminato, tota 

 superficie valvae hyalina ; valva inferior similis ; chromatophori brun- 

 nei, pyriformes, alterni vel oppositi. 



Habitat : In seawater of Honolulu Harbor, Hawaii, originally col- 

 lected by R. E. Johannes. 



Frustules short- to linear-oblong, or long-rectangular with rounded 

 ends, the latter type sometimes slightly, almost imperceptibly, con- 

 stricted in face (valve) view ; girdle view rectangular with rather 

 sharp (or scarcely rounded) corners ; valve surface flat and straight 

 apically, sometimes slightly depressed in the center ; valve mantle 

 narrow, girdle zone two to six times as wide as valve mantle, with a 

 lined appearance as if comprised of intercalary bands ; end view of 

 f rustule square-rectangular with rounded corners ; valve surface 

 mildly convex transapically, with rounded margins ; raphe a straight 

 narrow line ; valve with a median, narrow, transapical groove crossing 

 it at right angles to raphe, in girdle aspect the groove, due to focal- 

 depth refraction, with the appearance of a triangular or cone-shaped 

 bright spot resembling a central nodule (believed a false optical 

 effect) ; the slightly thickened corners of the valve end with the im- 

 pression of terminal nodules in girdle view ; valve surface markings 

 cannot be resolved with the optical microscope. Valves 5-10)u, long, 

 Z-Ajx wide. 



Chromatophores in young, actively growing cells are bright orange- 

 brown, more or less "tear-" or "pear-shaped," with truncate ends, one 

 in each end of the cell, with narrow ends toward the cell center, char- 

 acteristically alternate, much less frequently opposed (that is, on the 

 same side), occupying (estimated) one-third to one-half the cell vol- 

 ume, the alternate arrangement giving frequently a twisting, sigmoid, 

 scolio, or amphiproroid effect (actually not present). In older cells, 

 the chromatin material is either duller, darker brown, or paler, and 

 occupies more of the cell volume in a somewhat irregular pattern, but 



