282 On the Hermaphrodite mode of 



It appears that M. Bernard de Jussieu was the first tb 

 observe ova of the common brown polype, which he did when 

 travelling in 1743.* M. Trembley refers to this observa- 

 tion, of which he was made cognizant by a private letter from 

 M. de Reaumur. Trembley has described from his own re- 

 searches these rounded egg-like bodies in his Memoires, pub- 

 lished in 1744; and he also mentions the occurrence on other 

 individuals of the same species of the small conical tubercles 

 which we now know to be the spermatic capsules. Some 

 years later, Rbsel gave an excellent coloured figure of both 

 these bodies as they occur on separate individuals ; and they 

 were also later described by Pallas in 1766. Although the 

 nature of the ova was suspected by Trembley, yet he ex- 

 pressed himself doubtingly regarding them ; by some they 

 were considered as parasites, and by others both the ova and 

 spermatic capsules were regarded as possibly of the nature of 

 morbid excrescences. 



This state of uncertainty appears generally to have pre- 

 vailed till 1836, when the nature of the ova was ascertained 

 with greater precision by Ehrenberg, who took occasion to 

 examine them with care in reference to a resemblance alleged 

 by M. Turpin, to exist between the ova of Cristatella vagans 

 and the fossil Xanthidia. 



This resemblance Ehrenberg disproved, and showed that 

 even the greater similarity that might be alleged between Xan- 

 thidia and the ova of the common polype, was only of a very 

 general kind ; considerable differences in size, form, and struc- 

 ture being observable between the two bodies. He further suc- 

 ceeded in 1838, as is stated by Mr Owen in his lectures on 

 Comparative Anatomy (vol. i. p. 85), in detecting the exist- 

 ence of spermatozoa in the conical tubercles before referred 

 to as existing on other individuals of the Hydra, and 

 observed on some occasions the co- existence of the ovi- 

 gerous and spermatic capsules on the same individuals. 

 Notwithstanding these observations, the nature of the bodie* 



* An account of this observation was afterwards published in A bhand. der 

 Swed. Akad, 1746., B„ yiii, p. 211. 



