228 DESCRIPTIONS OF PREPARATIONS. 



(3) an internal faintly striated coat in which lie the degenerating nuclei of the 

 chitinogenous cells. The remaining cells of the ' embryonic mass ' become the 

 hexacanth embryo or proscolex, as it is called, and are arranged in an incom- 

 plete superficial set of more granular cells, and a contained set of clearer cells 

 which protrude at one pole, but are probably grown over subsequently. The 

 three pairs of hooks belong to the superficial set of cells. When the proscolex 

 is mature the original egg-shell and the albuminogenous layer of cells disappear, 

 and it remains invested solely, by its chitinoid coat. The ova of some other 

 Taeniae, e. g. T, mediocanellata s. saginata, appear to have a similar development. 

 The ovum sometimes undergoes regular and equal segmentation, e. g. in T. bacil- 

 laris, and then the albuminogenous layer is formed by a layer of numerous cells 

 raised from the surface of the embryonic mass. For figure of proscolex, see 

 PI. xiv. fig. 4. 



Van Beneden regards the albuminogenous layer of cells as the homologue of 

 the ciliated coat of cells or ' embryophore ' of some species of Bothriocephalus, 

 of Schistocephalus, and Ligula. Moniez, on the other hand, considers the chitino- 

 genous set of cells as the homologue of the same structure ; but he missed the 

 albuminogenous coat in T. serrata, &c., though he appears to have detected it in 

 other Tapeworms. Leuckart's account agrees essentially with Van Beneden's. 

 The latter thinks the successive coats of cells, formed as above, are to be con- 

 sidered as layers of ectoderm cells thrown off one after the other. 



The last joints of a Taenia contain the uterus alone of all the genitalia, 

 laden with the proscolices contained within their chitinoid coats. They are 

 detached either singly or in small numbers. For their subsequent fate, see next 

 Preparation. Some Cestoda possess a uterine aperture, and the ova are conse- 

 quently discharged at an earlier stage, e. g. Bothriocephalus. 



Parasites of Man and diseases resulting from them, Leuckart, transl. by W. E. 

 Hoyle, Edinburgh, i. 1886; the German original ' Parasiten des Menschen,' i. 

 (ed. 2), 1881 ; ii. 1876. Parasites, Cobbold, London, 1879. Vers Intestinaux, P. 

 J. Van Beneden, Paris, 1858 (or Supplement aux Comptes Rendus de 1'Acad. 

 des Sci., ii. 1861); Vers Cestoides, Id. Mem. de 1'Acad. Roy. Belg. xxv. 1850. Les 

 Cysticerques, Moniez, Travaux Inst. Zool. Lille, iii. i, 1880; Les Cestodes, Id. 

 pt. i, ibid. iii. 2, 1881. 



Lists of Parasites and Hosts, von Linstow, Compendium der Helminthologie, 

 Hannover, 1878. 



Cestodes of Hares and Rabbits, Riehm, Inaug. diss. Halle, 1881 (Zeitschr. 

 f. d. ges. Naturw. Giebel, 54, 1881). Taenia lineata, Hamann, Z. W. Z. xlii. 1885. 

 T. perfoliata, Kahane, Z. W. Z. xxxiv. 1880. Solenophorus, von Roboz (Beitrage, 

 &c.), Z. W. Z. xxxvii. 1882 ; Griesbach (Beitrage), A. M. A. xxii. 1883. Triaeno- 

 phorus, Megnin, Journal de 1'Anat. et Physiol., 1881. Ligula and Schistocephalus, 

 Kiessling, A. N. 48, 1882. 



Suckers, Niemiec, Recueil Zool. Suisse, ii. 1885. Connective tissue, &c., Griesbach, 

 on Solenophorus (supra). Ditto, and muscular tissue, Hamann on T. lineata (supra). 



Nervous system, Niemiec, Recueil Zool. Suisse, ii. 1885; cf. Lang, Mitth. 

 Zool. Stat. Naples, ii. 1881. 



Excretory system, Fraipont, Archives de Biol. i. 1880; ii. 1881. Pintner 

 (Untersuchungen, &c.), Arb. Zool. Inst. Wien, iii. 1881. 



