NOTES ON A NEW LAND PLANARIAN. 119 
which is about 0:2 mm. wide. This female atrium is connected 
posteriorly with a long tubular cavity (ut), which is about 1 mm. 
long and 0:1 to 0:15 mm. wide. The walls of the atrium and the 
tubular cavity are of the same structure, that is, the inner columnar 
ciliated cells, the outer thick muscular layer, and the outermost 
thick covering of the tubular glands. The glandular duct (gd), 
which is also invested with the tubular glands, opens into the female 
atrium. by a small pore which lies on the left side and at the anterior 
end of the tubular cavity. The short proximal portion (va) of 
this duct is much narrower and less glandular than the greater distal 
part; the former may probably be the so-called vagina. The 
glandular duct gives off a slender canal, which swells abruptly into 
a spacious cavity (sr) directed posteriorly and nearly horizontally. 



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OUTTA ANO 


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Tgave's Alp 
A semi-diagrammatic figure showing the copulatory organs seen from the 
left side: fa, female atrium ; gd, female glandular duct ; go, common genital 
opening ; ma, male atrium ; od, oviduct on the left side; pn, penis; sr, seminal 
receptacle ; ut, uterus ; va, vagina ; vd, vas deferens. 
The latter cavity communicates in a peculiar manner with the 
middle part of the tubular cavity (wt) through a broad aperture. 
The walls of this cavity, too, are essentially of the same structure 
as those of the atrium and the tubular cavity, so that we may admit 
that these three cavities were originally derivatives of one cavity or 
primary female atrium. It is, however, somewhat difficult to 
clearly identify these different compartments with von Graft’s 
diagrams illustrating the types of the copulatory organs. From 
the point of view of some structural and topographical analogies, 
I will call the three cavities respectively the female atrium, the 
uterus (the tubular cavity), and the seminal receptacle. That the 
uterus and the glandular duct communicate with each other by a 
connecting passage is a remarkable fact, which has been known only 
in Artiocotylus speciosus* (the Cotyloplanide). Von Graff states: 


* Von Graff, op. cit., pp. 201 and 209. Text figs. 58 and 59. 
