54 A. A]cock — On the Gestation of Elasmobranch Fishes. [No. 1, 



The striking feature was, that there was no connexion of any kind 

 between the foetus and the mother, and no evidence of any such pre- 

 vious connexion. 



The mucous membrane of the uteims, however, was covered with 

 an abundant glairy albuminous fluid, the secretion apparently of a layer 

 of thick-set papillas which formed its inner coat ; and the inference 

 seems irresistible that this fluid constituted the nutriment of the foetus, 

 and was, in short, a true uterine milk. Unfortunately, the examination 

 of the stomach of the foetus was delayed for twenty-four hours, when 

 the viscera had undergone such changes that the verification of this 

 theory was hardly possible. 



On removal of the fluid, which was then found to form a nearly 

 solid coagulum on the application of heat, the papillary layer of the 

 mucous membrane of the uterus was found to be of a vivid scarlet. 



The papillae themselves average about half an inch in length, and 

 are filiform in shape, and very delicate. They are so thick-set as to be 

 in contact when not floated out in water. 



Beneath them is a thick mucous layer rich in blood-vessels, and 

 outside this is (1) an inner circular and outer longitudinal layer of 

 muscle, and (2) a connective-tissue coat ; the whole aggregating in 

 thickness one-eighth of an inch. 



The thickness and compactness of the muscular coat is in striking 

 contrast with the loose spongy nature of the uterine walls in Garcharias 

 and Zygcena, and appears to indicate much greater parturient effort in 

 Trygon. 



b. Myliobatis nieuhofii. A female, with a disk seventeen inches 

 long and twenty-eight broad, was taken in the seine, by Mr. W. H. W. 

 Searle, off Cocanada, on the 31st March, 1889. 



The left ovary was full of large ova, and the distal end of its 

 oviduct formed a large globular swelling, with thick, firm, muscular 

 walls, and a uniform internal lining of broad flattened papillae nearly 

 half an inch long. 



On the posterior surface of this uterus, and closely adherent to it, 

 was an indistinctly tabulated gland-like organ, which, on section, was 

 found to consist of an aggregation of tubules with blood-vessels and 

 characteristic glomeruli, and a small amount of intertubular stroma. 

 The tubules were lined with large-nucleated, cubical, epithelium. Un- 

 fortunately, the other relations of this kidney were missed. 



A section through the uterus shows, from without inwards, (I) a 

 compact counective-tissue investment about one-eightieth of an inch 

 thick, with numerous large blood-vessels ; (2) a layer of unstriped 

 muscular tissue in transverse bundles ; (3) a layer of similar muscular 



