27 



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dent motions, consisting in the tightening and relaxation of their 

 coils : and more languid motions were afterwards noticed in some 

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

 ject from which they were obtained. 



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

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

 various more or less analogous productions, he states his 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 muscle, 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 

 Tanioides, 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 state the results of his own dis- 

 section of a fine specimen, 34- inches in length, for which he was in- 

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

 transparent, rather fine cuticle, which, 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 pnrietes 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 

 ventral parietes, on the contrary, are so transparent as to allow of the 

 contained parts being readily seen through them. 



The most essential difference between Linguatula and the Cestoidea, 

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

 tive organs being androgynous, with the oviduct continued from one 

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

 the 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 commences at the central ybrwrnew, or true mouth, 

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

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

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

 which continues with little variation 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 two elongated vesicles, 

 3 lines in length and more than 4- 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 Rotifera, &c. The ovary, which 

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



