27 



dent motions, consisting in thc tightening and telaSation of their 

 coils : and more languid motions were aftervvards noticed in some 

 specimens that were examined a fortnight after the death of the sub- 

 jcct from vvhich they were obtained. 



. Mr. Owen enters at some length into the ąuestion of the origin 

 of the cyst, and after comparing its structure and connexions witli 

 various more or less analogous productions, he statės bis opinion that 

 the cyst is adventitious, foreign to the Entozoon, and composed of the 

 cellular substance of the body infested, morbidly altered by the irri- 

 tation of the worm . 



. The reading of the paper was accompanied by the exhibition of 

 drawings showing portions of the infested musele, with magnified 

 representations of the cysts and of the worms contained within them ; 

 and specimens of the objects themselves were also placed upon the 

 table for examinatIon with the aid of Mr. Pritchard's microscope, 

 lent by him for that purpose. 



Mr. Owen also read a Paper " On the Anatomy of Linguatula 

 Teenioides, Cuv." After referring to the observations on the anato- 

 mical structure of this highly organized Entozoon, published by Cu- 

 vier and Rudolphi, he proceeds to statė the results of his own dis- 

 section of a fine specimen, 3 4- inches in length, for \vhich he was in- 

 debted to Mr. LangstalF. The whole body is invested with a smooth, 

 transparent, rather fine cuticle, \vhich, from maceration, and proba- 

 bly slight decomposition, had become detached. In this epidermis 

 there exist no marks of an annulate structure ; but the cutis, or mus- 

 cular parietės of the body, is distinctly divided into segments slightly 

 overlapping each other, and most obvious on the sides of the body, 

 which are its thickest and most muscular portions. The dorsal and 

 yentral parietės, on the contrary, are so transparent as to allo\v of the 

 contained parts being readily seen through them. 



The most essential diflFerence between Linguatula and the Cestoidea, 

 among vvhich it was first placed by Chabert, consists in the genera- 

 tive organs being androgynous, \vith the oviduct continued from one 

 end of the body to the other. Rudolphi, uncertain with regard to 

 tlie structure of the digestive organs, placed it among the Trema- 

 toda ; but the specimen under examination afFords conclusive evi- 

 dence of the justice of Cuvier's removal of it to the Nematoidea. The 

 alimentary canal ėomraences at the centrai for amen, or true mouth, 

 and runs straight to the opposite extremity of the body, terminat- 

 ing immediately above the orifice of the genital tube ; the oesophagus 

 being 4-rd of a line in length, and opening into a suddenly dilated canal, 

 •vvhich continues \vith little vaiiation of diameter to the anus. 



At the distance of a line posterior to the mouth, on the ventral 

 aspect of the body, the narrow extremities of t\vo elongated vesicles, 

 3 lines in length and more than -į- a line in diameter, adhere firmly 

 to the integument, the remainder hanging freely in the abdominal 

 cavity. These Mr. Owen considers to be analogous to the impreg- 

 nating glands of the hermaphrodite Roti/era, &c. The ovary, \vhich 

 is distinct from the tube so called by Cuvier and Rudolphi, is a nar- 



