250 SUMMARY OF CURRENT RESEARCHES RELATING TO 



similar to that of Bothnocephalus and Schistoce'phalus ; in Leuckartia, 

 wliere the sperm-duct is well developed, the cells of its walls give rise 

 to a plexus which allows of the direct entry of the spermatozooids. 



New Cestoid Worm.* — The remarkable Urocystis prolifer, which 

 is found parasitic in Glomeris limbatus, is to be noted for the fact that 

 it passes through the different stages of its life within the same host. 

 When in its vesicular condition it lives in the body-cavity, and in the 

 scolex stage it is encysted within the fat-body. In the former state 

 it consists of a head, a body, and a caudal vesicle. The oval head is 

 provided with four suckers, and a very long rostellum ; this last is 

 invaginated into the head at its posterior extremity, and into itself at 

 its anterior, giving rise almost to the appearance of a frontal sucker. 

 The inner wall of this infuudibulum presents a number of transverse 

 folds, and is armed by a crown of excessively small hooks. The body 

 consists of a very delicate membrane, and below the neck there is a 

 kind of pad formed of embryonic cells ; the caudal vesicle is oval, and 

 is excessively contractile. The whole parasite does not exceed an In- 

 f usorian in size. The following is its mode of multiplication : the joints 

 are developed successively, and break off when they become mature. 

 Ordinarily we find a vesicle entirely developed into a head, associated 

 with a bud which has the form of a caudal appendage ; at the moment 

 when the first signs of the scolex appear, the two individuals are very 

 slightly connected together. When it becomes detached the vesicular 

 bud is found to contain a perfect scolex. This last rapidly frees itself 

 of its caudal vesicle, and makes its way into the fat-body of its host. 



Here the scolex does not undergo any great modifications ; it takes 

 on a spherical form, and the embryonic cells in the wall of the 

 " body " are converted into elastic fibres. With certain relations to 

 Staphylocystis, it is at any rate distinguished from it by not forming 

 colonies. The definite host, whether bird or mammal, belongs, as 

 M. Villot thinks, to the Alpine fauna ; the Glomeris from which he 

 obtained his specimens was captured in the woods of La Grande 

 Chartreuse. 



Loss of Hooks and of the Scolex in the Taeniadae.t— M. 

 Megnin not only brings forward further evidence in support of his 

 proposition | that the armed and the unarmed states of a Taenia are 

 constant and successive in the same species, but that there is, further, 

 an equally constant acephalous condition ; in other words, the scolex, 

 just like the hydatid vesicle, is a transitory structure. " It is only 

 one more of the many means of multiplication of which Nature has, 

 among the Cestoda, shown herself so munificent." 



In certain species the detachment of the first rings is an expression 

 of the cessation of the functions of the scolex, which now ceases to 

 bud and to produce; its duty is at an end. It is now gradually 

 absorbed, first losing its hooks and then its suckers, till finally it 

 disappears altogether. As examples of these processes, thjs author 



* Comptes Eendus, xci. (1880) p. 938. 



t Journ. Anat. et Physiol. (Robin) xvii. (1881) pp. 27-45 (2 pis.). 



t See this Journal, ill. (18S0) p. 444. 



