376 Mr. C. 0. Wuterhouse on the 



embryos of several marsupial genera, including native bears 

 and opossums, and some kangaroo and wallabies. I must get 

 many more before I shall have enough to work out all the 

 problems of the development. I shall be deeply indebted to 

 any one who will inform me in time of an approaching kan- 

 garoo drive. It matters not to me whether the drive be in 

 New South Wales, Victoria, Queensland, or South Australia, 

 so long as the place be fairly accessible. A drive where the 

 kangaroos are yarded would be preferable. An answer, giving 

 an estimate of the number of animals likely to be obtained, 

 addressed to my headquarters. Board of Health Office, Sydney, 

 Avill reach me. 



" Yours, &c., 

 " In Camp, Burnett River, W. H. CaLDWELL." 



Queensland, 1884." 



I can only add an expression of thankfulness for having lived 

 to see solved, and mainly by Mr. Caldwell's persevering 

 researches, a biological problem which I have sought to deter- 

 mine since the date of a paper on the Ornithorhynchus in the 

 ' Philosophical Transactions,' 1832, p. 517. 



EXPLANATION OF PLATE XIIL 



Fig. 1. Anterior or ventral view of the female organs, urinary bladder, 



and cloaca (nat. size) of Echidna hystrix ; the right uterus laid 



open, and exposing a collapsed ovum. 

 Fig. 2. The same parts, with both uteri laid open. 



(In both figures : a, ovarium; b, abdominal orifice of oviduct, 6'; 



c, uterus ; fl, urogenital canal or cloaca ; e, urinary bladder ; 



f, uterine ovum ; g, hyalinion or outer tunic ; k, vitelline mass.) 

 Fig. 3. Ovum from tlie right uterus, with the vitelline or undeveloped 



embr\'o;i.'.l mass exposed. 



XLVI. — On the Coleopterous Genus Macrotoma. 

 By Charles O. Waterhouse. 



Having recently had occasion to examine some specimens of 

 the genus Macrotoma and to consult various Catalogues re- 

 ferring to this group of Longicorns, I was surprised in all 

 cases to find Macrotoma Hayesii^ Hope, placed as a synonym 

 of M. serrijjes, Fabr., the Munich Catalogue giving M. 

 llayesii as the male, and M. serripes as the female. I do not 

 know how this very great error originated ; but it is difficult 

 to conceive how any one who had compared the figures- given 



