16 KITTON, ON DIATOMACE^. 



C. antiqua are frequently found with the marginal band 

 detached. 



R. Archerii, O'M, fig. 12, is the upper valve of a Cocconeis 

 with the puncta abraded, probably it is C. costata of W. 

 Gregory [Cocconeis divergens, fig. 5, may be the same but the 

 lower valve). 



Eupodiscus excentricus, O'M, fig. 2, seems to be a valve of 

 Coscinodiscus minor of Kiitzing, with an abnormal marginal 

 development similar to a state of Amphitetras antediluviana, 

 fig. by Mr. Brightwell, in Vol. VIII of the ' Mic. Journ.' 



In conclusion, I will venture to observe that the publica- 

 tion of isolated and imperfect specimens not only do not ad- 

 vance our knowledge, but, on the contrary, are an hindrance 

 to the study of these minute forms, and it would be far better 

 to keep all such in an obscure corner of the cabinet or throw 

 them into the fire, than publish them with crude and im- 

 perfect characters. A far greater service would be rendered 

 to the study of minute forms of organic life, if the extent of 

 variation in one single species was made the subject of ex- 

 amination than the publishing a score of rare species. 



Description of a Netv Genus of Diatomaceje, and observa- 

 tions on the costtJB of Pinnularia peregrina. By 

 Frederic Kitton, Norwich. 



A valued correspondent has informed me that the form 

 described in the Synopsis as Gomphonema Fibula is not a 

 Gomphonema, but must be considered a new genus. 



Peronia, n. g., Brebisson and Arnott. Frustules solitary, 

 elongated, linear, and slightly cuneate, attached by the base. 

 Valves attenuated but obtuse at the base. Constricted and 

 subcapitate at the apex, destitute of nodule^ and median line, 

 striae transverse pervious (across the whole valve). P. 

 erinacea, Breb. and Am. ; Gomphonema tibula, Breb. MS. ; 

 G. Fibula, Kiitzing, Smith ; Synedra spinulceformis , Sm. 

 MSS. Sy7i. Fibula, Smith, in Brit. Mus. Cat., p. 33. 

 Fibula being more a clasp than the tongue or pin of the 

 clasp, is scarcely so good a name for the genus as the Greek 

 one Peronia, but, at the same time, is too closely allied to 

 permit it to be used for the specific name. This diatom 

 covers the leaves of Sphagnum, and the margin of the 

 decaying leaves of grasses like pins in a pincushion. 



