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118 H. CHARLTON BASTIAN ON THE STRUCTURE AND 
tubes. Mr. Busk, too, did not recognize the genital tube, and hence his assumption 
(most probable in such a case) that the Guineaworm was one of the intermediate or 
* nursing " forms of a worm, similar to the parent of Cercarie amongst the Trematoda., 
I was also much deceived at first by this peculiar arrangement, and unable to recognize 
any genital or intestinal tube, owing to the usual situation of the latter alongside one 
of the longitudinal muscles (Pl. XXI. fig. 22 d), where it for some time escaped obser- 
vation, appearing only as a faint band of granular matter; and it was not till on one 
occasion I observed this tube twisted on itself, and crossing one of the lateral spaces, 
that I saw what it really was, and obtained an insight into the correct anatomy of the 
worm. I have nowhere met with any reference to this great development of the genital 
tube, and its close adherence to the parietes of the body. 
I will now describe the structure of the uterus and ovarian tubes. 
The uterus is a powerful and highly organized sac, made up of four distinet coats—an 
external or peritoneal investment, a transverse or circular layer of elastic tissue, a layer 
of longitudinal muscular fibres, and a simple internal membrane. The peritoneal coat 
is a delicate membrane, having roundish or oval, nucleated, flattened epithelial cells 
scattered over its surface, varying from 3955th to gğçgth of an inch in diameter (Pl. XXII. 
fig. 36). The next coat is composed of a beautiful fibrous reticulated network of elastic 
tissue, as perfect as that met with in the middle coat of an artery, the fibres of which 
vary from 3555th to Tooth of an inch in diameter (Pl. XXII. fig. 37). The fibres have 
a cireular arrangement, and form a continuous investment of the whole uterine sae, 
stopping short abruptly at the ovarian tubes. "This coat is not easy to isolate, as the 
fibres mostly break off in the same line as the membranes on either side of it; occa- 
sionally, however, a portion may be seen projecting alone beyond the membranes. The 
network can be seen indistinctly through the external or internal coats. The third layer 
is an investment of very delicate longitudinal muscular fibres, lying close together, the 
individual fibres not being more than about 35355th of an inch in diameter (Pl. XXII. ' 
fig. 38). The internal coat is a delicate, homogeneous structure, serving the purpose of a 
mucous membrane. 
The small terminal ovarian tubes are rather less than an inch in length, and about 
goth of an inch in diameter. They are pretty constant in size throughout their extent, 
tapering only slightly towards either extremity (Pl. XXII. figs. 34, 35). The free ex- 
tremity is blunt and rounded or imperfectly lobed. Their structure is totally different 
from that of the large uterine sac, and seems closely to resemble that of the intestine, 
with which it agrees also in general aspect. There seems to be an inner homogeneous 
membrane, which is closely invested by a peritoneal covering prolonged from the uterus, 
but no intervening muscular or elastic coats. Amongst the granular contents of these 
tubes may be detected multitudes of nuclei and cell-germs, and in one or two instances 
I have seen one or even two of the full-sized young contained within them, but they 
are never distended in the same way as the large uterine sac is. 0 
This structure of the genital organs seems to agree closely with what Meissner * has 
described in Mermis albicans, if we omit the absence of a recognized vulva and vagina in 
Filaria medinensis. | 
* Loc. cit. — 
