Miscellaneous. 231 



of hairs. The Ixodes is very prolific, A single female confined in 

 a pill-box produced no less than 143 eggs, of which, on August 9^ 

 all but six were found to be hatched, and the young swarm actively 

 trying to escape from their prison. The egg-shells, both of Ixodes 

 and Argccs, are composed of tough chitine. The husbandmen, in 

 trying to relieve their suflfering flocks and to destroy the ticks, 

 have employed men to pick them off the sheep, throwing the ticks 

 on the ground ; but this practice is now shown to be simply pro- 

 pagating the evil by sowing the pregnant vermin broadcast. 



Cauterbuiy, August 20, 1872. 



On the Embryonic Form of the Gordii. By M. A. ViLioT. 



The embryo of the Gordii, which has hitherto remained unknown,, 

 has no resemblance to the adult form. It is a microscopic cylin- 

 drical worm, scarcely 0*205 millim. in length, and 0-045 millim. in 

 breadth, in which we may easily distinguish a head, a body, and a 

 tail. 



The head is as broad as the body and entirely retractile ; it is armed 

 with a triple circlet of stout pricldes, and terminates in front in a sort 

 of trunk or sucker. The trunk is rigid, owing to the four strong 

 styles which serve it as a framework. The prickles of the first two 

 rows (that is to say, those near the base of the trunk) are of the same 

 form, arrangement, and size ; they are six in each row, the upper 

 ones slightly covering the lower ones ; and they are partly inserted 

 into a triangular sheath, which gives them the form of a lance-head. 

 Those of the third row are implanted at the base of the head. They 

 alternate with those of the first two rows, and do not resemble them 

 either in number or in form ; their sheath is nearly quadrilateral, 

 and their free extremity is much longer ; they are also stouter and 

 more resistant ; lastly, we count seven of them instead of six, as one 

 of the sheaths bears two. The head, in its movements of protrusion 

 and retraction, behaves like the trunk of the Echinorhynchi ; it turns 

 back upon itself from its apex to its base, and from its base to its 

 apex, causing its prickles to describe an arc of 180 degrees. "When 

 it is out of the body, the points of the prickles are directed backwards ; 

 in the contrary case the opposite. Their arrangement is then com- 

 pletely inverted : the trunk, wliich was in front, is thrown completely 

 to the back ; then come successively the prickles of the first, second, 

 and third rows, united in bundles and constituting with the trunk a 

 solid rod in the centre of the body ; the extremities of the prickles 

 of the third row slightly project beyond the extremity of the body, 

 which is then armed with a short but very resistant dart. 



The body presents numerous transverse folds, very close together 

 and very regular, so that it might be thought to be composed of true 

 rings. 



The tail, which is a little narrower than the body, is separated from 

 it by a deep constriction ; it is also very distinctly annulated, and 



