JOURNAL OF MICROSCOPICAL SCIENCE. 
DESCRIPTION OF PLATES XII, XIII, 
Illustrating Dr. Wallich’s paper on Triceratium and 
Hydrosera. 
PLATE XII. 
Fig. 
1.—Front view of 7riceratium serratum. 
2.—Valve of ditto. 
3.—More highly magnified view of one of the connecting plates during 
division, showing serrated edge and arcuate band. 
4.—T.. jimbriatum, front view. 
5.—Valve of ditto. 
6.—Fragment of valve exhibiting cellular structure. 
7.—Profile of a fragment, showing depth of cells. 
8.—Profile of fimbriz. 
9.—Three of the fimbrize, seen under a power of 600 diameters. 
10.—7. pentacrinus, front view. 
11.—Valve of ditto. 
12.—Connecting membrane of ditto. 
13.—Portion of ditto. 
14.—7", pentacrinus, four-sided variety. 
15.—T. annulatum. 
16, 17.—Two newly separated frustules, showing the supersistent counect- 
ing band, formed of the siliceous plates of their halves of the parent 
frustule ; the other or second layer having receded from these, and 
remained attached to the other newly liberated frustules. 
PLATE XIII. 
1.—Portion of Hydrosera triquetra in natural state. 
2.—Frustule of ditto, seen from above, as laid on one of its sides, the 
central angular ridge only being in focus. 
3.—Connecting membrane of same, showing one of the plates forming the 
annulus, with its imperfect septa. The other plate behind it out of 
focus. 
4.—End view of valve of same, showing cellulation under a power of 
950 diameters, the spines at the angles, and processes on one 
side. 
5.—Broken valve, showing one of septa. 
6 —Portion of same valve under power of 350 diameters, showing reticu- 
lated structure. 
7.—Portion of filament of H. compressa in natural state. 
8.—Frustules of same undergoing division, and exhibiting the lateral 
appendages. 
9.—Connecting membrane of same. 
10.—End view of ditto. 
11.—Side view of ditto. 
12.—Enlarged view of lateral processes. 
