Miscellaneous. 
245 
the expense of the length. The bulb shows through the thin inte- 
gument, and without close examination may be taken for a third 
orifice. The penis is perforate, and has a dilated cavity within the 
bulb. Immediately above the penis I indistinctly observed a some- 
what lobated organ, which appeared to join the penis at its base by 
a narrow portion. This is probably the testicle, for it was the only 
thing I could discover in connection with the genitalia to correspond 
to it. 
In two individuals only could I see part of the female organs. This 
consisted in two sigmoid tubes or oviducts, which could be traced 
from the generative orifice a short distance forwards, one on each 
side of the penis. 
I could detect no traces of a nervous system. 
The eyes, so called, have been previously described. It is still a 
question with many, whether these, as well as the corresponding 
deep black points existing in very many of the lower animals of the 
invertebrate series, subserve the purpose of eyes ; and some anato- 
mists have even gone so far as to deny the sense of sight to the 
comparatively perfect eye of many gasteropodous mollusca. The 
experiments which are made to test the existence of this sense in 
these organs for the most part are exceedingly fallacious, generally 
being performed by concentrating the light upon them through a 
lens. Insects, and even serpents and frogs, I find will frequently 
bear the impression of a sudden glare of light produced in this way 
without any inconvenience, at other times they will seek to avoid it ; 
but Helix albolahris will occasionally retract its tentacle when so 
disturbed, and Phagocata will frequently raise its anterior extremity 
and move from the too great light. From their position, which is 
always such as to be well exposed to the influence of the light ; from 
their structure, imperfect as it is in many cases, and their connec- 
tion with the nervous system when this exists, I am led to conclude 
that in all cases they are organs of vision. 
The general sensibility of Phagocata is very considerable, that is, 
it contracts with great readiness from the slightest disturbance. The 
contraction has much the appearance of being involuntary, and is 
very like that of the Medusae. When an individual is irritated at 
any point, contraction commences there, and thence rapidly extends 
throughout the animal, and the only appearance of volition is in the 
effort to escape ; but if the touch be too rude, apparently involuntary 
contraction takes place suddenly, and appears to destroy all power of 
volition for the moment ; the animal however soon revives from this 
state and glides off with its accustomed speed. 
Some experiments which I performed upon Phagocata confirm the 
statements that the Planariae are capable of repairing injuries. When 
an individual is cut into two, both parts after a time become distinct 
and perfect animals. Division carried to a greater extent in some 
instances results in as many perfect animals as there are parts, but 
generally I have found that when cut into more than three or four 
pieces, the intermediate pieces are apt to die, and sometimes the ex- 
tremities do not survive. — Proc. Acad. Nat. Scien. Philadelphia. 
