426 On Utero-gestation in Trygon Bleekeri. 
[The colours of the mother are dark brown dorsally and olive- 
brown ventrally, except on the thorax and abdomen, which 
are blotched with white. ] 
§ 7. Recapitulation and Conclusion. 
To recapitulate: in Trygon Bleeker’, as twice observed in 
the pregnant state, we find a single uterus containing a single 
naked foetus unattached structurally to the mother; we find 
the uterine mucous membrane to be produced into long villi 
which consist almost exclusively of blood-vessels and glands ; 
and we find the viscid, turbid or milky, and richly albuminous 
secretion of the latter free in the uterine cavity. In the 
present case the secretion is observed unchanged in the 
spiracles, and in coagula filling the “ duodenum” and the 
anterior part of the spiral gut, of the foetus. 
Elsewhere Professor Wood-Mason and I have shown that 
in the nearly related Pteroplatea micrura the uterine villi 
(trophonemata) actually pass into the spiracles of the fcetus ; 
and I have quite recently observed this same disposition of 
the trophonemata in Trygon walga. 
The specimen from which these particulars have been 
recorded was too large for preservation; its skin has been 
sent to the Indian Museum. 
Besides the classical text-books and the classical memoir of 
Johannes Miiller, ‘ Ueber den glatten Hai des Aristoteles ” 
(Abhand. Ak. Wiss. Berl. 1840), the following papers refer 
specially to the subjects of the uterine villi and aplacental 
viviparity of the Batoidei :—John Davy, ‘‘ Observations on 
the Torpedo,” Phil. Trans. 1834; ‘Trois, “ On the Uterine 
Villi of Myliobatis noctula [and Centrina Salviant],” Atti 
del Instituto Veneto, vol. ii.; Haswell, P. L.8., N.S. Wales, 
vol. ii. 1889, on Urolophus; Alcock, ‘ Observations on the 
Gestation of some Sharks and Rays,” Administration Report 
of the Marine Survey of India for the Official Year 1888-89, 
and Journ. As. Soc. Beng. vol. lix. part ii. (Vrygon Bleekert 
and Myliobatis Nieuhofiz) ; WWood-Mason and Alcock, “ On 
the Uterine Villiform Papille of Pteroplatea micrura,” Proce. 
Roy. Soc. vol. xlix., and “ Further Observations on the 
Gestation of Indian Rays,” Proc. Roy. Soc. vol. 1. (Zrygon 
walga, Pteroplatea micrura, and Myliobatis Nieuhofir). 
EXPLANATION OF PLATE XIX, 
Fig. 1. The distal half of a trophonema, x 10, showing m, the non- 
glandular margin in which runs a, the artery; ard g, the glan- 
dular centre with v, the central vein. 
