FEMALE ORGANS OF FISHES. 575 



attached by two diverging ligaments to the abdominal walls. If 

 a little powdered charcoal be sprinkled on the ovarian orifices and 

 ligaments exposed by opening the abdomen in a fresh caught 

 female Dog-fish, the particles will be seen to move towards and 

 enter the common oviducal aperture, indicative of a ciliated 

 epithelium in the serous membrane, which may aid in the 

 transport of the ova to that aperture. The oviducts, narrow, 



and with thin tunics at their commencement, diverge from each 



* ~ 



other, arching over the fore part of the ovaria, and then descend 

 along the ventral surface of the kidneys, to terminate at the 

 lateral and posterior parts of the cloaca, ib. s. A glandular body, 

 ib. o, is developed in their coats, after the first, fifth, or sixth part 

 of their extent, and their terminal half or third part, ib. r, is 

 dilated; the sizes of the glandular and of the uterine parts of 

 the oviduct are usually in inverse proportion : in the oviparous 

 Plagiostomes the gland is large, the uterus small, and the reverse 

 obtains in the viviparous species, fig. 384. The inner surface of 

 the Fallopian portion of the oviduct presents longitudinal or very 

 oblique folds of the delicate mucous membrane : but near the 

 aperture the folds resolve themselves into minute compressed villi. 

 The glandular part varies in structure as w r ell as in size in different 

 species. In the viviparous Dog-fish {Spinax acanthias) it consists 

 of two elliptic flattened lobes, of laminated structure, the free 

 surface presenting minute transverse stria?, beset with pores, the 

 orifices of secerning tubes, the aggregate of which composes the 

 layer of glandular substance. In the oviparous Homelyn (Raia 

 maculatd) the lobes of the large rudimental glands are reniform, 

 and consist of close-set layers of secerning tubes. In the Tope 

 (Galeus) the lobes of the gland present the same essential 

 structure, but are conical, subspiral, and hollow. The uterine 

 part of the oviduct in the viviparous Dog-fish, fig. 384, r, has 

 the lining membrane produced into longitudinal folds, with wavy 

 margins, each of which contains a single vessel following its 

 sinuosities, and sending off branches to the parietes of the 

 oviduct : the folds gradually subside at the outlet of the oviduct. 

 In the oviparous Dog-fish (Scylliuni] the folds of the lining 

 membrane of the corresponding part of the oviduct are oblique, 

 and their vessels are derived from trunks in the walls of the 

 oviduct, and are distributed in minute and tortuous ramifi- 

 cations on the folds. 1 The uterus of the Smooth Dog-fish 

 (Scoliodon, M. ; Emissole lisse, Cuv.) shows several uterine 



1 xx. vol. iv. p. 136, 



