436 Hough—Description of a Printing Chronograph. 
branching canals, burrowed in ee monadigerous mass, but into 
the great circulatory apartmen 
Spongilla set oe Jas—Cl. 
DESCRIPTION OF FIGURES OF PLATE IL. 
The following letters apply to identical part~ in all of the figures. a, Inves ue 
Sectio 
hae 
membrane; outer division.—a', onal profile of the cytob astema of a.—b 
. Cells in the thickness of me Lo — seer - se about ‘me ‘spioules ge i 
is ; : 
sti brane, with th surface 
porary junction (by contact only) of ‘te os tr (a) and inner © divisions iP the 
investing membrane.—c, Inve ting membrane; epithelioid inner division, in sec- 
tional Pipa be avegcanea 8 between monad-c Ubes-comaoy J ncthi of the divi- 
R ps 2 a 
—%; m 
chambers and monad shonpk —1, Aperture of h.—j, Monads, or the body proper 
in figs. 3 and 3a.—k, “pamriaas collar of j.—1, Flagellwm.—n, Nucleus.—os, Minor 
ostioles.—v. Bie ye 
Fig. 1. Magnified 320 dinmetons Part of a biped young Spongilla, of an o oblaté 
— form, te about z's Of an inch i in diameter. On the right is presented 
f the investing membrane and the underying ieeastieel mass, 
On the left the focus is so adapted as to be fixed on a face-view of the monad-mass, 
and at the same time on a sectional protile of the investing membrane at a’, 5°, ¢, 
Magnifie ed 780 errno Interior Ler @ monad-chamber, seen through 
Forti ; the monads appear in end view, and crowded together side by side 
like a pavement wor 
Fig. 3 segnited 1 600 af we ah A single monad, as seen in profile in the 
monad-chamber. Onl © contractile Mer eal gase present in this specimen. 
The eplindrcal collar On is extended to its u 
;600 eters. het ened, front view of a monad; 
the the body iy Gi) in the Sigeneo; the hollow cylinder (%) projecting toward the ob- 
like a dark hoop, and the flagellum (I) in the center appearing as a black 
Fig. 4. ified 780 diameters, — view of a monad-chamber, —— 
the aperture (#) into profile, as well as the monads aeacat lie at the same ley 
thus showing their conve ergence about ng psa open 
Arr. LV. Miers ene of a Printing Chronograph; by G. W. 
Hovea, Director of the peers Observatory. 
rved. e gre 
point of ‘hataaeke and saving of labor, over the old eye and - 
ene coop y used, led to the almost general adoption © 
e new plan. 
| hth, the past ten years the idea of constructing a chrono- 
graph, which ahoahl print with type the time of the observ® 
tion, has been entertained F t fiv 
