6 AMERICAN LOCALITY OF AMPHITETRAS ANTEDILUVIAN A . 



This may prove to be only a variety of the preceding, with which it often occurs 

 at the above-mentioned localities, but, at present, I think it best to keep them 

 separate. The sparsely punctate bases of the one, and the closely punctate surface 

 of the other appear to offer a sufficient distinction between them. 



3. Anisscns caelatiig, B. 



(Plate, Figs. 3, 4.) 



Margin of the bases strongly grooved with unequal lines proceeding from the 

 circumference towards the centre, but leaving a well-defined cruciform figure, con- 

 taining on one bar the two processes with sets of converging curves, and on the 

 other bar two sets of beautifully reticulated and anastomosing lines. Umbilicus 

 distinct, smooth. Diameter of base xoVo"t^ i^- Found in sand washed from West 

 India sponge, and in soundings from Mobile Bay. 



4:. Anliscus radiatus, B. 



(Plate, Fig. 13.) 



Lorica small; bases with radiant punctate lines ; umbilicus wanting. Diameter 

 T'o^o'o*^^ ^^ To^oo'^'^- -^ minute species, presenting the characteristic mastoid pro- 

 cesses of the genus Aiillscus, but having no distinct umbilicus, and only slight indi- 

 cations of the peculiar curved lines of the preceding species. Found in mud from 

 New York Harbor, and in the mud of the Hudson River at West Point; also at 

 Rockaway, Long Island, New York. 



IV. 



A:\iERicAN Locality of Amphitetras antediluviana, Ehr. 



I have published, in the American Journal of Science, notices of American locali- 

 ties of the beautil'ul species of Mhmia and Bicldnjphia, but I had long sought in 

 vain for the allied but much rarer form of Amphitetras antediluviana, which has 

 never hitherto been noticed as an American species. I have at last, however, 

 detected a few frustules of this species (See Plate, Fig. 21) in soundings from 

 Edgartown Harbor, Massachusetts, for which I am indebted to A. D. Bache, Esq., 

 Superintendent of the Coast Survey. I presume that a careful search among the 

 parasites upon the Algae in the vicinity of Edgartown would be rewarded by the 

 discovery of an abundance of specimens of this interesting species. 



In company with the a!)ove,*at Edgartown Harbor, and at the outer buoy near 

 Cape Pogue, were found the following Diatomaceae : — 



Viz : Actinoptychus senarius, Ehr. Ampbora libyca, Ehr. 



Biddulphia pulchella, Gray. Gallionella sulcata, Ehr. 



Eupodisci with from three to seven feet, and always opaque and white; perhaps new. 

 Auliscus pruinosug, B. Auliscus punctatus, B. 



Navioula ? lyra, Ehr., abundant. Triceratium favus, Ehr., very abundant. 



This locality is also remarkable for the abundance of Polytlialamian forms, 

 among which (besides various species of Textilaria and the common nautiloid 

 forms) were noticed beautiful species of a Lagena, resembling the L. laevis of Wil- 



