A NEW FIELD FOR THE MICROSCOPIST. 
129 
At the outset, considerable difficulty will doubtless be ex- 
perienced in the satisfactory definition of the hyaline collar 
characteristic of all the members of this group, a most careful 
manipulation of the light being often requisite to show this 
structure to advantage. It frequently happens again that when 
the entire contour of the wineglass-shaped collar is not to be 
distinguished, its presence is indicated by the clearer outline of 
its two lateral margins, which, standing out at an acute angle 
from the perpendicular line formed by the central flagellum, 
present the aspect of two additional hair-like processes. The 
appearance of this organ, when seen as described in the last sen- 
tence, is indicated at Plate IV. fig. 41, illustrative of the so- 
called “ animalcule with ear-like processes,” figured many years 
since by Mr. Carter, but which undoubtedly represents a species 
of Salpingceca with the characteristic collar indistinctly seen. 
In a similar manner other species now shown to belong to this 
newly discovered collar-bearing group have from time to time 
been imperfectly figured by various authorities, who, when en- 
countering them, have-not employed sufficient magnifying power 
or that mode of illumination requisite for the interpretation of 
their true character. 
Having, with the assistance of these few hints, made himself 
familiar with but two or three only of the interesting types here 
introduced to his notice, the investigator will experience but 
little difficulty in extending the circle of his acquaintanceship 
with the same, and can scarcely fail before long to become so 
absorbed in admiration of the infinite variety of form and vital 
phenomena they present, as to regard as lost any further time 
bestowed on the markings of either Diatoms or Podura scales — 
et hoc genus omne. 
EXPLANATION OF PLATES. 
With one or two exceptions all the figures in the accompanying plates repre- 
sent the objects delineated as seen with a magnifying power of from 500 to 
2,000 diameters. 
PLATE III. 
Fig. 1, 2. Adult colonies of Codosiga cymosa, Sav. Kent. 
„ 3. A single monad of the same species in an encysted state. 
„ 4. Adult colony of Codosiga umbellata, S. K. 
„ 5. Adult colony of Codosiga alloides, S. K. 
„ 6. A single monad of the same with the body and collar retracted. 
„ 7. Monad of the same species in its fully expanded state. 
„ 8. Adult individual of the solitary form Monosiga august at a, S. K. 
„ 9. Adult colony of Codosiga pidcherrima , J. Clk. 
NEW SERIES, VOL. II. — NO. VI. K 
