Description of Neiv Species of Diatoftis. 13 



attached to Hypnum. And it is the only gathering hitherto 

 made, so far as I am aware. It can hardly be considered other 

 than an extreme variety of M. circulare, with the strongly 

 marked pervious costae of this species in s. v., and the conse- 

 quent crenulation or intra-marginal punctation of the valves 

 in f. v., nearly obliterated, approaching indeed the smoothness 

 of Licmop/wra. The discovery of this intermediate form was 

 the more interesting, as it enabled me to place Greville's and 

 Arnott's Perofiia erinacea where it belongs. This singular form, 

 which was at first considered as a Gomphonema^ and subse- 

 quently made the type of a new Genus, of which it is the sole 

 species, is now related to M. intermedium, as the latter is to 

 M. circulare, in other words it is a smooth form of Meridion, 

 and of course the connecting link with Licmop/wra, all the 

 species of which hitherto enumerated are marine. M. interme- 

 dium is No. 238, and M. erinaceum {Gomphonema fibula^^Perojiia 

 erinacea) is No. 239 of my ''Species Typicae Diatomacearum." 



Navicula Xutzingiana, n. sp. H. L. S. Avranches, Normandy, 

 France, M. de Brebisson, Frustules linear, valves scarcely 

 inflated, with rounded ends, and three or four conspicuous 

 striae radiating from the central nodule, and which are prom- 

 inent also, along with the central nodule, in f. v. Frustules 

 in f. V. quadrangular, frequently adhering and forming a short 

 filament {Diadesmis), and with two distinct intra-marginal 

 (bead-like) vittae, at either end: Length .0006 to .00085 ! 

 breadth, f. v. .00033, s. v. .00021. Striae about 50 in .001. 

 Plate III, fig. 3. 



This small, but distinct form, which from the coherence of 

 the frustules into short filaments might almost be termed a 

 Diadesmis, I received from M. de Brebisson labeled ^'Amp/iiprora 

 arenaria." A glance at the figure I have given will show that 

 it does not belong to the genus Amphiprora as now limited, 

 but that it is a true Navicula. As there is already a Nav. 

 arenaria, I give to it the name of the celebrated Algologist, 

 Kutzing, whose numerous figures of Diatomaceae, though but 

 mere outlines, sketched by aid of a microscope, that would 

 scarcely be looked at, much less through, at the present day, 

 possess more of the character and catch more of the spirit of 

 the living species, than many of the representations of modern 

 days, and whose descriptions are models of accuracy and con- 

 ciseness. The more I study his plates the more I admire their 



