NO. 7 NEW SPECIES OF MARINE PENNATE DIATOM — CONGER 5 



been possible. Material preserved in formalin, alcohol, or other liquid 

 preservative is of uncertain and doubtful value. The living culture 

 may best serve as confirmatory or "type" material. 



In the active, healthy cultures there is some range in the size and 

 shape of the cells, and the size, shape, and arrangement of the chro- 

 matophores, but this is well within the limits of expectation. In the 

 large numbers of specimens observed the growth pattern is very con- 

 sistent and typical, and the incidence of distorted or otherwise abnor- 

 mal forms is exceedingly low. The generally healthy vigor of the 

 species implies that it thrives under cultural conditions and adapts 

 readily to them. The adaptability suggests it as a dependable and 

 useful culture organism for many experimental purposes. The dis- 

 covery of Achnanthes subhyalina suggests the importance of wide- 

 spread "culturing" as a valuable exploratory method, as yet meagerly 

 employed, for the recognition of many minute, obscure, and transient 

 forms which have so far eluded detection and may continue to do so 

 in the future without this method. It is more and more recognized 

 that these watery, next to invisible, transitory forms may comprise a 

 substantial, functionally important constituent of the micropopulation 

 of the ocean. Hitherto they were a "blindspot" in our studies, which 

 cannot afford to be overlooked any longer. They will be, at best, a 

 tedious, difficult, and special study. 



