BY R. BROOM. 577 



Though the female thus disappointed me in my hope of finding 

 accurately the period of incubation, it enabled me to arrive at an 

 approximate idea of the period of gestation. The evidence on 

 this point would have been more conclusive had the sexes been 

 k^pt apart, but as the male died on the 18th, and was in a very 

 low condition for some days previously, impregnation could not well 

 have taken place later than the 12th, and as during the period of 

 captivity neither ai3peared to have any interest in the other 

 except to use the body of its companion as a stepping stone while 

 endeavouring to climb out of the box, it seems highly probable 

 that impregnation had taken place when the specimens were 

 captured. If this be so, the period of gestation would be about 

 26 or 27 days, and even if this were not so, as impregnation could 

 not well have taken place later than the 12th, the period of 

 gestation could not be less than 18 or 19 days. 



The eggs of my specimen appeared considerably paler than that 

 figured by Semon,"^ being of a light cream colour. The unbroken 

 egg measured 14 mm. in its long axis, and about 12*5 mm. across. 



I must express my thanks to Prof. Wilson for having had an 

 opportunity of seeing Semon's work. 



Addendum (7th Feb., 1896). — I have recently had an opportunity 

 of seeing the person who first observed the two Echidnas referred 

 to above — Mr. Angus Mclnnis. He states that the two were 

 lying together on a slight hollow at the root of a tree, and so far 

 as he could observe front to front, but as on his near approach 

 the two separated and endeavoured to escape, he could not be 

 certain of their exact positions before being disturbed. He, how- 

 ever, assures me that on picking up the male its copulatory organ 

 was protruding about a couple of inches; so that there can be 

 little or no doubt but coitus had just taken place. This, he 

 further states, was on the day previous to my getting them, or 

 4tli September. This additional information remoA^es the previous 

 uncertainty, and enables us to fix the period of gestation at about 

 28 days. 



■' R. Semon. " Zool. Forsehungsreisen in Australieii u.d. Malay. 

 Aichipel. Band ii.; Monotremen imd Marsupialier." Jena 1894. 



