KITTONj ON DIATOMACE^. 17 



Phmuhu'la pe.regrina. — Whilst examining the valves of 

 this form with a high power (800 diameters), I accidentally 

 discovered that the costte are transversely striate on their 

 internal surface. The strioe are about 50 in '001 of an 

 inch. I have not been able to detect this peculiarity in 

 any other species, nor has it been noticed in any work with 

 which I am acquainted. Dr. Gregory, in ' Mic. Journ.,' Vol. 

 Ill, Trans., p. 15, says, " I may mention that a friend informs 

 mc that the stri» on P. gracilis have been found by him to 

 be moniliform, although the fact may not yet be thoroughly 

 established. This, it ivill be observed, corresponds tvith Mr. 

 Smith's observation on the striae of P. peregrina^ But where 

 does Smith say so ? 



I may mention that oblique light at right angles to the 

 valve is necessarv to brino- out the striec. 



Vol. VIII. XEW SEK. 



