8 Norman, on Diatomace<p. 



large quantity of the material, when it is to he hoped that it 

 may prove more ahundant. The hlank centre, large size, and 

 unusual distance from the margin of the nodules, together 

 with the large blank spaces around the same, render this a 

 well-marked species. 



Judging from the occurrence, in abundance, of the various 

 species of Heliopelta in this deposit, together with Eu^jodiscus 

 Rogersii, Craspedodiscus elegans, AuJacodiscus Crux, Scep- 

 troneis caduceus, Triceratium solenoceros, condecorum, undu- 

 latum, and acutum, there can be little doubt that it is 

 identical with the Bermuda earth of Professor Bailey, the 

 locality of which has hitherto remained in much doulit. For 

 the small quantity received I am indebted to Messrs. Sulli- 

 vant and Wormley, of Columbus, Ohio. The deposit was 

 discovered, I believe, by Dr. Johnson, of Baltimore, near 

 Nottingham, in Maryland, not far from the Patuxent River, 

 and within a moderate distance of Piscataway, where the well- 

 known rich deposit occurs. 



Bermuda Hundred, on the James Biver^ in Virginia, is 

 distant about a hundred miles from Nottingham, but as all 

 the waters of this district find their way into the great 

 Chesapeake Bay, it is quite possible that the locality suggested 

 by Dr. Arnott may have furnished the sample of Bermuda 

 earth originally sent to this country by Dr. Bailey. I under- 

 stand, however, from Messrs. Sullivant and Wormley, that 

 Dr. Johnson had examined the country at Bermuda Hundred 

 without finding any deposit whatever. When the larger 

 supply of the Nottingham material arrives, I shall be glad to 

 supply my friends with a portion. 



6. Eupodiscus ovalis, n. sp.. Norm. (Fig. 7). — Valve 

 elliptical, nodule single, submarginal; granules arranged 

 in radiating lines, crowded near the margin, sparser towards 

 the centre. Colour, tawny brown. Length of valve *0020" 

 to -0035." 



Marine, stomach of Ascidians, Shark Bay, Australia. 



This species approaches Eupodiscus fulvus, differing, how- 

 ever, in the elliptical shape, altered position of the nodule, 

 which in the latter is nearer the margin, and also in the 

 arrangement of the granules, the disc being divided into 

 regular segments by the longest lines of granules. 



7. Navicula hullata, n. sp.. Norm. (Fig. 6). — Valve 

 elliptical, extremities slightly produced. Striae in a marginal 

 and two central bands ; marginal bands of unequal width. 

 The smooth space between the striated bands studded with 

 a line of circular bosses. Striae moniliform, 14 in "OOl". 

 Length of valve -0065 "; breadth -0030". 



