1865.] H. v. Schlagintwcit on Indian Meteorology. Ill 



showing some stage of embryonal development in the spring terrestrial 

 Monotreme. As to the hairy and aquatic Ornithorhynchus, the impreg- 

 nated females in which ova were found in the uterus, of small size, and 

 prior to the formation of the embryo, were caught on the 6th and 7th of 

 October. Young Ornithorhynchi, measuring in length in a straight line 

 1 inch and |ths, were found in the nest on the 8th of December. The 

 period of impregnation, therefore, in this species, in the locality of the 

 Murrumbidgee River, is probably the latter end of September or beginning 

 of October. Females captured in the latter half of October and in the 

 month of November, would be most likely to have ova in utero, exhibiting 

 stages of embryonal development. 



The author concludes by quoting a letter informing him that an Orni- 

 thorhynchus in captivity had laid two eggs, with a soft unvascular cover- 

 ing, each about the size of a Crow's egg. They were destroyed without 

 examination. Had they been preserved in spirits or opened on the spot, 

 the inference of the ovo-viviparous character of the animal might have 

 been confirmed or otherwise. According to the Report, these alleged eggs 

 must have resembled those of the Viper. Now the young Viper is pro- 

 vided with a specially and temporarily developed premaxillary tooth, for 

 lacerating the soft, but tough, shell of its egg, and so liberating itself. 

 From this analogy, the author conceives that the young Monotremes may 

 be provided with a horny or epidermal process or spine upon the inter- 

 narial tubercle for the same purpose. This temporary tubercle is obviously 

 homologous with the hard knob on the upper mandible of chelonians and 

 birds, by which they break their way through the harder calcareous covering 

 of their externally hatched embryo. 



The paper was illustrated by drawings of the female Echidna, of her mar- 

 supial pouches and young, of the mammary glands, and of the female organs 

 of generation. 



March 9, 1865. 



Major-General SABINE, President, in the Chair. 

 The following communications were read : 



I. " Numerical Elements of Indian Meteorology. Series II. Insola- 

 tion, and its Connexion with Atmospheric Moisture." By HER- 

 MANN VON SCHLAGINTWEIT. Communicated by the President. 

 Received December 27, 1864. 



(Abstract.) 



The author regards as an approximate measure of insolation the differ- 

 ence of the maximum temperatures observed by two similar thermometers, 



