50 
GEOLOGY OF THE FIRST DISTRICT. 
B. Recent. 
Achnanthes pachypus. 
Actinocyclus hexapterus. 
Cocconeis oceanica. 
Dictyocha panduriformis. 
— splendens. 
Echinella moniligera. 
Fragellaria catena. 
— pinnata. 
Gomphonema subtile. 
The following papers of Prof. Bailey, upon the subject of the Infusoria, are from the 
American Journal of Science, Vols. 41 and 42: 
Those organized beings which Ehrenberg has placed among the Infusoria, in the family 
Bacillaria, present almost equal claims on the attention of the zoologist, botanist, and geo¬ 
logist. Containing, as this family does, those obscure organic bodies which form, as it 
were, the connecting links between the animal and vegetable kingdoms, and which appear 
to possess characters belonging to both, the student of either zoology or botany must ex¬ 
amine them; and, in fact, the very simplicity of their structure renders them peculiarly 
proper for the observation of many phenomena of great physiological interest. The geolo¬ 
gist must attend to them; for the discoveries of Kiitzing, Fischer, and especially of Ehren- 
berg, have shown that many of these minute bodies possess siliceous coverings, which occur 
in vast abundance in the fossil state, and which form the minutest, and yet not the least im¬ 
portant nor least interesting, of the series of - “ nature’s medallions.” 
Believing that some account of the structure, classification, etc. of this family would be 
acceptable to many in this country, and that figures of our most remarkable species would be 
of interest to the students of this family, both in this country and in Europe, I have devoted 
for some time past the very few leisure hours at my command, to the preparation of the fol¬ 
lowing sketch. As an apology for the very imperfect state in which I now present it, I must 
state that my knowledge of the labors of othe’rs is necessarily very slight, as it is almost im¬ 
possible to procure in this country any works relating to this branch of natural history. Of 
the many European works which contain figures of these obscure beings, scarcely one has 
been at my command; and as no one in this country has previously studied this subject, I 
have had to trust almost entirely to my own observations. 
To avoid the risk of adding to the already burdensome synonimy, I have not attached any 
names to the species which I believed new, or which I could not determine satisfactorily, 
and shall merely refer to them by the numbers given to the figures representing them. I hope 
that these figures will enable some of the learned students of this family in Europe to decide 
which species are new; and perhaps if this paper should meet the eyes of Ehrenberg, he 
may oblige us by furnishing the authentic names of the species represented in the accompa¬ 
nying plates. 
Grammatophora mexicana. 
Navicula campylodiscus, 
— bicarinata. 
— crucigera. 
— Iseta. 
— reticulata. 
Podosira moniliformis. 
Spongia capitata. 
Spongia clara. 
—• neptuni. 
— obtusa. 
— uncinata. 
Globulus porosus. 
Spirulina vivipar. 
Biloculina tenella, 
Textularia plicata. 
