THE MICROSCOPE. 105 
DESCRIPTION OF FIGURES. 
Fig. 1. From the fat body of a frog near the periphery of a cross 
section of one of the processes. Drawn with camera lucida. 
B, V, blood vessels. The nuclei of the endothelial cells and the con- 
tained blood corpuscles are shown. A, A, special plasma cells 
in which the intra-nuclear line has formed. B, cell in which the 
deposit of fat is recent. C, C, D, E, F, H, cells showing pro- 
gressive accumulation of fat, with division of the nucleus. 
Fig. 2. Special plasma cell before the appearance of the intra- 
nuclear line. 
Fig. 3. Cell showing the nucleus being divided along intra- 
nuclear line. The fat (F) following like a wedge into the space so 
formed. 
THE DIATOMS OF MOBILE, ALABAMA. 
K, M. CUNNINGHAM. 
N TWO previous articles which appeared in this Journal, I com- 
municated on methods of collecting and cleaning diatoms, and 
the manner of selecting and arranging the same. In this article it 
is proposed to give the result of pursuing the instructions therein 
given, by referring to a type-plate of the diatoms of Mobile, and 
immediate neighborhood, which was made by me in the month of 
September, 1888, with the object of permanently placing on record 
the desultory and prolonged study of the diatoms of the above named 
region, covering a period of ten years. Circumstances, however, 
prevented the final result from being as comprehensive as it should 
have been; nevertheless, what has been accomplished has some merit 
in itself, and is capable of interesting those who have been, and are 
now interested in those beautiful unicellular algze, the Diatomacez. 
The type-slide referred to, contains closely aggregated in a 
small parallelogram, of about one-tenth of an inch in width, by 
four-tenths in length, nearly 1,500 selected diatoms, representing 
about ninety distinct species, of which a list of the species, as deter- 
mined by the Hon. J. D. Cox, is appended to this article. The 
type-slide was, furthermore, by voluntary request, sent to Dr. D. B. 
Ward of Poughkeepsie, who microphotographed it in five sections, 
thus enabling the preparation to be afterwards reproduced as a 
whole, by the portrait camera, of such a magnitude as to be satisfac- 
torily inspected by the eye, unaided by other optical means. To 
prepare the slide, it became necessary to clean up samples of diatom- 
bearing material from twenty localities, comprising salt, lake, 
