DEVELOPMENT OF FISHES. 



291 





Female Organs : 

 Spinax, Hunter. 



stages of growth, being developed more consecutively. The approxi- 

 mated or confluent abdominal apertures of the oviduct (ib. h) are an- 

 terior to the ovarium, between the liver and the peri- 

 cardial septum ; they form together a heart-shaped 

 opening, with entire margins, attached by two diverg- 

 ing ligaments (ib. c) to the abdominal walls. The ovi- 

 ducts narrow, and with thin tunics at their commence- 

 ment (ib. d d), 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. A glandular 

 body (ib. e) is developed in their coats, after the first 

 fifth or sixth part of their extent, and their terminal 

 half or third part (ib./) is dilated: the sizes of the 

 glandular and of the uterine parts of the oviduct are 

 usually in inverse proportion : in the oviparous Plagi- 

 ostomes the gland is large, the uterus small, and the 

 reverse obtains in the viviparous species. The inner 

 surface of the Fallopian portion of the oviduct pre- 

 sents 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 well as in size in different species. 

 In the viviparous Dog-fish (Spinax accmthias) it consists of two 

 elliptic flattened lobes, of laminated structure, the free surface pre- 

 senting minute transverse stria3, beset with pores, the orifices of 

 secerning tubes, the aggregate of which composes the layer of 

 glandular substance. In the oviparous Homelyn {Baia maculata) 

 the lobes of the large rudimental glands are reniform. Prep. 3234. 

 shows well the inner free margins and interspaces of the close-set 

 layers of secerning tubes. In the Galeus the lobes of the gland present 

 the same essential structure, but are conical, subspiral, and hollow. 

 The uterine pai-t of the oviduct in the viviparous Dog- fish has the 

 lining membrane produced into longitudinal folds, with wavy 

 margins, each of which contains a single vessel following its sinuosi- 

 ties, and sending off branches to the pai'ietes of the oviduct : 

 the folds gradually subside at the outlet of the oviduct. In the ovo- 

 viviparous Dog-fish (ScylUum) the folds of the lining membrane of 

 tlie corresponding part of the oviduct are oblique, and their vessels 

 are derived from trunks in the walls of the oviduct, and arc dis- 

 tributed in minute and tortuous ramifications on the folds (prep. 2683). 

 The preparation (No. 2684) of the Smooth Dog-fish (Co/e?/*- levis ; 

 Emissolc lisse, Cuvier) shows several uterine cotyledons developed 



