236 
Steplianocliasmus Looss 
by the intestinal trunks. It is made up of two very distinct portions, 
the posterior or egg-forming portion (Figs. 1, 2 and 10, 42), which 
consists of two thick transverse folds and lies directly in front of the 
ovary, and the anterior or egg-storing portion (43) consisting of three 
or four folds which contain the eggs. The posterior or egg-forming 
portion represents the ootype of most distomes and is filled with sperm ; 
it also contains a considerable number of the large eggs embedded in 
the sperm. This structure has been called the receptaculum seininis 
by Linton (1910). It is true that it contains sperm, but it is never¬ 
theless not homologous to the receptaculum of other distomes inasmuch 
as it is a part of the uterus and contains also eggs. A receptaculum 
seininis in the ordinary sense is not present in any of the worms of this 
genus. An ootype is thus also absent in the form met with in other 
distomes. The condition of these organs in this worm may be con¬ 
sidered a primitive one in that a specialized ootype has not developed 
from the posterior portion of the uterus. The eggs are of large size, 
measuring 0-06 mm. by 0-045 mm., and are few in number. 
The yolk glands (Fig. 1 , 47) are very voluminous, extending from the 
hinder margin of the acetabrdum to the hinder end of the body, reaching 
thus farther forwards than in any member of the genus heretofore 
described. They completely occupy the lateral areas of the body, 
lying both dorsal and ventral to the wide intestinal trunks (Fig. 3, 47) 
and are bounded medially by the genital organs which occupy the 
medial areas of the body. The yolk glands consist of large follicles 
which are arranged in transverse rows extending from the periphery 
towards the centre of the body. The main transverse yolk ducts 
(Fig. 10, 41) meet dorsal to the ovary (Fig. 2) and not between the ovary 
and the anterior testis as in all other members of the genus, and form 
a large yolk reservoir (Fig. 10, 48) from which a long median yolk duct 
(23) passes antero-ventrally and unites with the Laurer’s canal and 
the oviduct to form the uterus. 
The Laurer’s canal (21) is rather long and passes from the common 
meeting point with the oviduct, the median yolk duct and the uterus 
in a dorso-median direction to the opening in the dorsal body wall 
(Fig. 3, 38). In the section shown in this figure it is seen to be filled 
with sperm which protrudes from the opening. The cells constituting 
the shell gland (37) are grouped together about the Laurer’s canal, the 
median yolk duct, the yolk reservoir and the oviduct between the 
ovary and the dorsal body wall. 
It will be noticed that the complex of organs just described is not 
