Utero-gestation in Trygon Bleekeri. 410 



placenta, (2) a glairy milky or hloo ly fluid, which he sup- 

 posed to be in some way absorbed by the foetus, and (^i) the 

 gradual increase in weight ot the foetus as gestation proceeded. 

 Davy left unsettled the questions (1) of the immediate origin 

 of the milky fluid, (2) of its immediate destination, and (.'}) 

 of the direct manner of increase in size of the embryo. 



It has been reserved for the ' Investigator,' thanks to the 

 profusion of the Batoid flshes in the warm estuaries of tiie 

 Coromandel coast, to extend and amplify the observations of 

 Davy, and to draw a more finished and exact picture of the 

 aplacental viviparity of this interesting group. The material 

 collected by the * luvestigator ' confirms the older observations 

 as to (1) the absence of any structural connexion between 

 foetus and mother, (2) the presence of a creamy albuminous 

 fluid in the gravid uterus, and (})) the increase of the foetus in 

 size and weight as pregnancy advances; while it adds to our 

 knowledge the following necessary facts : — (4) the presence 

 of special secretory glands in the mucous membrane of the 

 gravid uterus, (5) the existence of arrangements for con- 

 ducting the uterine secretion into the pharynx of the foetus, 

 and (6) the presence of the unchanged or little changed 

 secretion in the alimentary canal of tlie foetus. 



As references to original papers are appended, it is not 

 necessary here to do more than mention that the above obser- 

 vations have been made, and in every instance verified at least 

 once, in Trygon Bleekeri^ Blytli, Trygon xoalga^ M. & H., 

 Pteroplatcea micrura (Bl. Schn.), and Myliohatis Nieuhofii 

 (Bl. Schn.). In the first-named species, which was the first 

 to come under my notice, the observations were made under 

 particularly unfavourable circumstances, and I therefore seek 

 an opportunity, in describing a second pregnant female of this 

 species recently captured by the * Investigator,' to make 

 some corrections and numerous additions to .my original 

 report. 



§ 2. The Pregnant Female and the Gravid Uterus of 

 Trygon Bleekeri. 



A female of Trygon Bleekeri^ Blyth, measuring in extreme 

 length, from tip of snout to tip of tail, 9 feet 7 inches, in 

 length of disk 3 feet, and in greatest breadth of disk only an 

 inch and a half less, was caught in Cocanada Bay (at one of 

 the mouths of the river Godavari) on the 12th January last. 

 The abdomen was distended, being strongly convex instead 

 of flat. 



On opening the abdomen the internal organs of generation, 



32* 



