O NEW SPECIES OF DIATOMACEAE. 



Single frustules of Tetragramma americana were found by me several years ago 

 in the mud of the Hudson River, in mud from Eockaway, New York, and Charles- 

 ton, South Carolina ; but I have nowhere found it in such abundance as in the mud 

 of the St. Sebastian River near St. Augustine, Florida, and at Tampa Bay, Florida. 



VI. 



. New Species of Diatomaceae, 



In this article I present brief descriptions, with figures of a number of American 

 Diatomaceae, which I sujopose to be hitherto undescribed. 



1. Asaiplsora sta«ii'optea*a, B. 



(Plate, Figs. 14, 15.) 



Elliptical, elongated; margins striated; central portion crossed, as in Stauropfera, 

 by a broad band. Length, y oVo ^^ ; width at the middle, a little more than xoVo ^-^ 

 of an inch. Found in Algae from Halifax, Nova Scotia. 



fS. Climacosphaenia elongata, E. 



(Plate, Figs. 10, 11.) 



Frustules elongated clavate, rounded at the ends, and having numerous cross- 

 bars on the minutely striated bases. Striae most distinct near the edges, and 

 exceedingly delicate in the middle portions of the bases. Pedicels long, branching, 

 supporting many fan-shaped groups of frustules, as shown in the following wood-cut. 

 It occurs in great numbers, parasitic upon Algae; from Garden Key (Tortugas), 

 Florida. Length of frustu.les, y^f g th of an inch. 



I have distributed some specimens of this form under the manuscript name of 

 C. ramosa, B. ; but, as I now believe that branched pedicels may also 

 belong to other species, I have changed the name, and now rely on 

 the elongated clavate form of the frustules, and their excessively 

 minute striations, to distinguish this species from those described by 

 Ehrenberg and Kiitzing. The striae on the G. elongata can be made 

 out without much difficulty, near the edges of the shell, but to trace 

 them completely across the middle regions of the bases requires excel- 

 lent lenses and careful management of the light. In fact, these lines 

 are even finer than those upon the Providence Grammatopliora. In our figure 10, 

 these cross-lines are well represented, although the figure itself almost requires to 

 be looked at with a magnifying glass, in order to distinguish these lines. 



Chaetocei'os Iboreale, B. 



(Plate, Figs. 22, 23.) 



Body oblong in side view, elliptical when seen endwise. Horns excessively long 

 (30 to 50 times as long as the body), and armed with numerous minute spines. 

 Longest diameter of the body li". Shortest diameter S". Length of the horns 

 IG"". Length of the spines 1"". Habitat, St. George's Bank, Atlantic Ocean. 



Ehrenberg describes several recent species of Ghaetoceros, as occurring in the 



