160 Prof. Gene on the Generation of Ixodes. 



instead of being microscopic are often of large size. While many 

 are but one or two lines in diameter, others are one or two feet. 

 The large Fungia, with its stellate surface and sprinkling of eme- 

 rald tentacles around its central mouth, is one of the most beau- 

 tiful objects of the coral reef. 



The foregoing remarks are presented as an introduction to a 

 more particular account of the structure and habits of zoophytes. 



XVIII. — Observations on the Generation of Ixodes. 

 By Prof. Gene. Communicated by Alfred Tulk, M.R.C.S. 



Though some time has now elapsed since a paper bearing the 

 above title was read by Professor Gene of Turin at the Scientific 

 Association held in Milan in 1844, and subsequently reported in 

 its ' Transactions ' during the past year, we have been induced 

 to avail ourselves of the latter source to give the reader an ac- 

 count of the facts therein recorded concerning the manner in 

 which the generative functions are performed by both sexes of a 

 genus of Tracheary Arachnida, belonging to the tribe Acarides ; 

 and in trespassing upon the reader's attention thus late in the 

 day, we would urge as an excuse the very striking relation, if 

 only approximative in kind, between the organ employed by the 

 male Ixodes to copulate with the female, and the palpi as mini- 

 stering to similar uses in the Araneides or true Spiders. The 

 Professor showed how DeGeer had been the first to observe the 

 copulation of the Ixodes, which act consists on the part of the 

 male, which is very much smaller in size than the female, intro- 

 ducing its rostrum into the orifice situated upon the middle of 

 her sternum between the coxse of the last pair of legs ; but inas- 

 much as neither DeGeer, Hermann, and subsequent naturalists 

 were certain whether this strange union was actually one of a 

 sexual character, he commenced by adducing a large number of 

 observations of his own, tending to remove any doubt that might 

 exist upon the question, by proving that the male actually inserts 

 his rostrum and that only into the female aperture, and that its 

 fecundating organs consist of two small white and fusiform bodies 

 which during this insertion emerge on the right and left of the 

 inferior labium, while upon the retraction and consequent disap- 

 pearance of these organs, the male, being then detached from the 

 female, scarcely appears the same creature. 



In the year 1806 Chabrier had announced that the females of 

 Ixodes gave birth to their ova through the oral opening or mouth ; 

 a statement, however, refuted ten years afterwards by Pastor 

 Muller of Odenbach, who observed that the ova issued from the 

 proper sternal canal of the female, who in expelling each ovum 



