Prof. Gene on the Generation of Ixodes. 161 



effected this by means of a conical and tubulose tubercle. This 

 observation, tending to contradict the assertion of Chabrier, was 

 afterwards repeated and confirmed by Lucas, but neither he nor 

 Muller had seen the half of what takes place in Ixodes during 

 the emission of ova. 



The female of Ixodes, after having been fecundated by one or 

 by several more males in succession, proceeds without any delay 

 to perform this long operation. To this effect she commences 

 by depressing upon the sternum all the palpi that compose the 

 rostrum, when there is seen to be protruded with an easy gliding 

 motion from beneath the dero-cephalic plate a turgid vesicle of a 

 white colour, and which from its being terminated by two lobes 

 of equal consistency and colour, having at their apex a most 

 minute aperture, our author designates provisionally the vesica 

 biloba. When this organ, which had been seen neither by Muller 

 nor Lucas, has been well dilated so as to project beyond the 

 rostral palpi, the animal everts the pectoral canal and gives exit 

 to the oviduct, which being protruded like the feeler of a snail, 

 proceeds at once to disburden itself between the lobes of the 

 vesica. This clasps, compresses, and appears as if sucking the 

 oviduct for a few seconds ; but after this the oviduct is retracted, 

 re-enters the sternum, leaving an egg between the lobes of the 

 vesicle, which clasps it firmly, turning it to and fro in all direc- 

 tions, and vibrating now and then in a spasmodic manner. Four 

 or five minutes having elapsed, during which time the ovum re- 

 mains between its lobes, the vesicle disappears by re-entering its 

 internal situation j the ovum is left upon the inferior labrum, 

 and this being elevated along with all the palpi that compose the 

 rostrum, thrusts the ovum upon the dero-cephalic plate or in 

 front of the body. These acts are renewed for as many ova as 

 the female may have to discharge. 



The Professor did not know what might be the office of this 

 bilobed vesicle. He suspected at first that it might be the recep- 

 tacle of the semen : that deposited by the male during coition in 

 the oviduct was transferred thither, so as to accumulate, by means 

 of some internal channel, but the existence of such a communi- 

 cation the anatomy failed to reveal, added to which it would re- 

 quire too long and improbable a transit. He imagined likewise 

 that from this organ might issue the glutinous fluid with which 

 the ova are besmeared, but this conjecture also had to be re- 

 nounced, upon ascertaining that they were already viscid and 

 adhesive at their immediate exit from the oviduct. In such a 

 state of doubt recourse was had to an experiment, which pro- 

 duced the following important result. Having punctured, with 

 the point of a fine needle, the vesica biloba of various pregnant 

 females, so as to prevent its further distension, he then saw, that 



Ann, fif Mag. N. Hist. Vol. xviii. N 



