36 (OBUOLD, ON GYRODACXyLUS ELEGANS. 



These authors have collectively treated tlie subject in so 

 exhaustive a maimer, that observers in this country can 

 barely hope to add important novelties ; yet I would especi- 

 ally invite those who are fortunately possessed of " Wenham's 

 binocular arrangement/^ to make the attempt, as there are 

 points which an instrument thus furnished will materially 

 assist in elucidating. 



In common with several of the above-mentioned investiga- 

 tors I have noticed the second generation (or '^ daughter " of 

 the so-called nursing animal) of Gyrodactylus elegmis to 

 contain in its interior clear evidence of a third generation. 

 Indications of this third progeny may be seen, whilst the 

 embryo is still within the body of the " nurse " or parent ; 

 but it acquires much greater distinctness immediately after 

 birth. In one instance I had a very satisfactory opportunity 

 of watching the process of separation. The embryo (or 

 daughter) commenced showing itself externally by a slight 

 bulging near the centre of the body of the parent ; the in- 

 teguj3ient of the latter yielding on all sides of the bud-like 

 projection, and in such a manner as to convey the idea of a 

 vaginal opening, although the channel was not actually 

 demonstrable. As Mr. Bradley observes, there is an evident 

 effort on the part of the young creature to free itself from 

 the parental envelope; but I did not find the tissues to 

 exhibit any evidences of injury, such as tlie expression " tear- 

 ing " might seem to imply. On further protrusion it became 

 e^ddent that the budding portion of the young corresponded 

 with the centre of its body, which, in a little while, assumed 

 the appearance of a semicircular band, or horse- shoe-shaped 

 loop. Subsequently the upper or anterior end of the band 

 became detached, the free extremity being at once recognised 

 as the head of a young Gyrodactylus eleyans, furnished with 

 its two characteristic ventricose lobes. About this time a 

 pair of strong, backwardly curved hooks also came into view ; 

 these were attached to the ventral surface, and corresponded 

 in all respects vdih. those figured by Nordmaun. Curiously 

 enough, I noticed these spines in one or two other specimens, 

 and I believe they altogether escaped INIr. Bradley's obser- 

 vation. A considerable interval elapsed before the broad 

 posterior end of the animal could be disengaged, but imme- 

 diately this was effected the sides of the parental envelope 

 closed in upon the opening, and all that remained behind 

 was a small cavity or sac indicating the position recently 

 occupied by the young Gyrodactylus. Altogether the process 

 occupied about five minutes from the commencement of the 

 '■^ budding " to the closure of the assumed vaginal passage. 



