DR. T. S. COBBOLD, FURTHER OBSERVATIONS ON ENTOZOA. 



555 



the external cliitinous capsule presents the same characters as in T. dispar; at either 

 pole of the eg^, where the shell terminates abruptly, an inner transparent membrane 

 projects, in the form of a mammillary process (fig. 15). None of the eggs I examined 

 appeared to contain fully developed embryos, but the interior yolk-mass exhibited evi- 

 dences of segmentation, many of them displaying two nuclei. These ova have a longi- 

 tudinal diameter of -sioth to aio^^i of ^'^ i^ch. 



Fig. 2. 



Ym. 1. 



Fie. 3. 



Figs. 1, 2, 3. a, Epidermis; b, cutis ;c, cut ceecal end of the testis; d, seminal duct; e, intestine; f, intro- 

 mittent muscle surrounding g, the sheath of the penis ; g', infundibuliform portion ; g", exserted portion, armed 

 with minute retroverted spines ; </'", flask or cup-shaped expansion of the free extremity of the sheath ; /(, rings 

 formed by contraction of a portion of the sheath ; i, penis ; i", infundibuliform upper extremity of the penis 

 or spicule ; i'", free pointed end of the same ; k, an oval granular mass in one of the flask-shaped expansions, 

 apparently consisting of spermatic particles ; I, cloacal cavity ; m, anus. Drawn, with the aid of a camera, from 

 specimens mounted and preserved in glycerine. 



In regard to the solution of Kiichenmeister's hypothesis, which assumes the encysted 

 Trichince to be only immature forms of the more highly developed TriGJiocephulus, my 

 experiments have again been attended with merely negative results ; but this has possibly 

 arisen more from the unsuitableness of the particiilar hosts selected and operated on, 

 than from any other cause. From economical considerations, I confess to have refrained 

 from experimenting on sheep and pigs. On the 8th of December, 1859, I fed a rabbit 

 with portions of raw potato, on which were placed three fresh female TrichocephaU, all 

 of them being readily devoured. On the 13th January following the rabbit was destroyed, 

 and carefully examined, when neither TricliiiicB nor eggs of Trichoceplialus could be 

 detected. On the day above mentioned I also fed a chicken with three other fresh Tri- 

 chocephaU ; these worms having all been previously obtained from the giraffe. The bird 

 perished from exposure to severe cold on the sixth night succeeding the experiment. 

 Wlien, however, I dissected it several days afterwards, although the muscles showed no 

 T?'ichince, I was to a certain extent gratified to find several egg-shells of the Tricho- 

 cephaU still lodged in the intestinal caeca. Most of the egg-capsules were empty ; but a 

 few of them exhibited thinly scattered and disintegrated contents*. 



* Since the above was written, I observe that Leuckart's recent investigations disprove the notion that Trichiiue are 

 the young of Trichocephalus. See his treatise entitled ' Untersuchungen iiber Trichina spiralis, zugleich in Beitrag 

 zur Kenntniss der Wiirmkrankheiten.' 4to. Leipzig u. Heidelberg, 1860. See also ' Ann. des Sci. Nat.,' 4me ser. 

 tom. xiii. p. 318. 



VOL. XXIII, 3 B 



