320 ME. P. H. GOSSE ON THE DKECTOHS CHAEACTEE OF THE EOTFFEEA. 
mass to the hinder mass {d\ which is connected with the foot {g) and the great protru- 
sile penis. In the midst of this latter mass is situated the group of opake white gra- 
nules (/), which are always so conspicuous in male Eotifeea. The central part of the 
body is occupied by the spermatic sac (e), — a great pyriform vesicle, connected by a 
bottle-like neck with the head-mass, and apparently terminating posteriorly in a round 
form, where, however, a distinct corrugation probably marks an orifice closed by a 
sphincter, which leads to the discharging duct. On pressure, this sac is seen to be filled 
with bodies having a vermicular motion, and, on the pressure being continued, it bursts, 
giving issue to a number (about thirty) of spermatozoa (fig. 22). These spermatozoa 
are comparatively of great size, being g-^th of an inch long ; they consist of a slender, 
nearly cylindrical body, merging into a long whip-like tad, which keeps up a quivering 
undulatory motion for several minutes after exclusion. With these are also extruded 
many spicula-like bodies (fig. 23), much more minute, somewhat fusiform, shghtly 
curved, and motionless. 
The penis (fig. 21) is, as usual, thick, and united to the foot, terminating in a short 
truncate tube, which I could not see to be ciliated. A few crimson pigment-cells, 
exactly agreeing with those of the eye, are usually seen in some part or other of the 
body, apparently in contact with the inner surface of the integument. 
27. In the middle of the summer of 1850 I discovered the males of two or three 
other genera. The first of these was the curious form which I have named Sacculus 
viridis* (fig. 24). I have had no opportunity of seeing the birth of females of this 
species, all the specimens that came under my observation (that bore eggs at aU) cariy- 
ing either one or two eggs of like size and appearance. From one of these eggs (fig. 25), 
Avhich, before matmity, are much clouded and spotted with granules and globules, a 
young was produced in my live-box, which was, I doubt not, a male (fig. 26). I could 
not detect any eye (though this organ is conspicuous in the parent), nor any intemal 
organization ; nothing but a confused assemblage of granules and globules ; even the 
ordinary opake masses were not present. The form somewhat resembled that of an 
amphora with a short wide neck ; the frontal ciha were very large, but the motion was 
not rapid, nor was the animal wild, as male Eotifeea usually are. 
28. Polyarthra platyptera is another form, which, from its habit of camTiig its 
deposited eggs, afibrds facilities for investigations regarding its sexuality. Finding it 
numerous in July, with eggs attached, I discovered that these presented the same 
diversity that I have mentioned above (§13, &c.). I isolated one with six small 
eggs attached, measuring y^th x -s^th of an inch. Presently afteiwards I foimd 
another, with a single egg attached, measuiing y^nd x of inch. This 
egg was truly oval, being sharper at one end than at the other. Several of the 
smaller eggs were hatched together, about twenty-four hour’s after isolation. They 
* From the description and figure of Dr. Letdig, I have no doubt this is identical with the genus Asco- 
morpha of Peett. I had, however, characterized and named it in the ‘ Annals and Magazine of Natural 
History ’ for September 1851, a year before M. Peetx’s work was pubhslied. 
