CURTIS: LIFE HISTORY OF PLANARIA MACULATA. 543 
Reproductive organs were of coarse fully developed in these speci¬ 
mens and I studied their anatomy casually while endeavoring to 
ascertain new facts regarding the function of the uterus, penis, etc., 
during the egg laying. At this juncture I was surprised to read in 
a recent paper by Woodworth (’97) the following sentence: Pla- 
naria macidata is the commonest of our fresh-water planarians and 
was the first one to be described (Leidy, 1848) ; however, nothing 
has been published regarding its sexual organs, and I am unable to 
offer anything in this regard; not one of the hundreds of specimens 
that came under my observation was sexually mature.” 
Since the anatomy of the most complex system of organs in this 
common species is entirely unknown, or at least unrecorded, I have 
availed myself of the opportunity to study them in their fully devel- 
oped state and T shall describe the main features of their structure, 
although there is nothing strikingly different from what has been 
found in closely related forms. The relative position of the dif¬ 
ferent parts may be seen from figure 56 (plate 19), though this rep¬ 
resents them in an immature condition. The atrial oro;ans are 
shown by dorsal and lateral views (pi. 12, figs. 33, 34). From fig¬ 
ure 56 it is seen that the testes are numerous and extend from the 
region of the ovaries almost to the tail. Although a few large folli¬ 
cles are to be found extending up between the gut lobes, the rest 
are packed closely together in the ventral region and are never 
found dorsal to the gut. Their lateral extent is seen in a transverse 
section of the animal (pi. 18, fig. 60) to be from a point about half¬ 
way between the lateral margin and the nerve cord to within a 
short distance of the median line. In front of the pharynx and 
behind the genital atrium, each nerve cord divides the testes of its 
side in such a way that in whole preparations there often appear 
two irregular rows on either side while in the region of the pharynx 
and genital atrium the inner row of either side is lost. Everywhere 
they are close together and from the ovaries to the tail hardly a 
transverse section can be found that does not cut a half dozen or 
more. In longitudinal sections they are found closely following 
one another, there being about seventy-five on either side. 
The testicular canals (vasa efferentia) are everywhere found con¬ 
necting one testis with another or the testes with the vasa deferentia. 
It has seemed to me, in studying these fine canals, that there is no 
reason for doubting that each testis has a definite connection either 
