^ 102. 



THE HELMINTHES. 



105 



CHAPTER II. 



MUSCULAR SYSTEM AND ORGANS OF LOCOMOTION. 



§102. 



The muscular system is well developed with the Helmintbes ; its primitive 

 fibres are flattened, and never transversely striated. In the Cystici, and 

 ■Cestodes, the muscles are least distinct, although in Cysticercus there can 

 be no question as to the muscular fibres which traverse in every direction 

 the walls of the caudal vesicle.'^' Equally distinct is a subcutaneous layer 

 of longitudinal fibres in the rings o^ Bothriocephalus and TaeniaS-^ More- 

 over from the great contractility of the rings, and especially those of the 

 cephalic portion of the Cystici and Cestodes, there must be muscular fibres 

 toncealed in the parenchyma, but which from their tenuity escape our 

 rbservation. In the Ti-ematodes, having also an extreme contractility, a 

 :arge portion of the parenchyma of the body is composed of a muscular 

 Teticulated tissue, the transverse and longitudinal muscles of which embrace 

 the various organs in a retiform manner.''^' In the Acanthocephali, the 

 Gordiacei, and Nematodes, the general movements of the body are due to 

 a subcutaneous muscular layer, which surrounds the visceral cavity in a sac- 

 like manner. Its longitudinal and transverse muscles are quite distinct 

 from each other ; and their fibres, although parallel, communicate with each 

 other by angular anastomes, and in this way form a net-work. ^^' 



In most of the Nematodes, the longitudinal muscles form four, large 

 bands, two upon the ventral, and two upon the dorsal surface. These 



In the Cestodes, this error is unnecessary, for in 

 the posterior portions of their body the eggs can 

 ■easily be distinguished from the corpuscles ; more- 

 over, these last are the most numerous about the 

 neck and anterior rings, — localities where the 

 genital organs are scarcely and sometimes not at 

 ^11 developed. It may be added, also, that these 

 bodies dissolve in a weak acid with the escape of 

 gas, while the eggs of Taenia under the same cir- 

 cumstances remain unaffected. In the Cystici, 

 which are sexless, and where therefore eggs are 

 vainly sought for, these corpuscles, as to their 

 structure, chemical composition, and position, so 

 closely resemble those of the Cestodes, that it ap- 

 pears strange that they have always been taken 

 for eggs. JEschricht (Nov. Act. Acad. Leopold 

 Carol. Vol. XIX. Suppl. alter. 1841, p. 59, 103), 

 not having jjerceived that they contain carbonate 

 of hme, has described them as elementary gran- 

 ules, and thinks that they have a nutritive function 

 analogous to that of the blood and lymph corpus- 

 cles. 



Gulliver (Med.-Chir. Trans. VI. London, 1841, 

 p. 1; see lViKsmann''s Arch. 1841, II. p. .314) has 

 given an exact description of those of Cysticercus, 

 but he also has taken them for eggs. In Taenia 

 Jilum, linea, serrata, and infundibuliformis, 

 they are spherical or oval ; and in the first two 

 gpecies, Goeze (Versuch einer Naturgesch. d. 

 Eingeweidewürmer, p. 393, Taf. XXXII. A. fig. 6, 

 V, 12) has taken them for eggs, and the concentric 

 rings of the calcareous layers for the coils of the 

 embryo. With those of Cysticercus cellulosae, 

 and pisiformis, the discoid form prevails ; I have 

 •often seen here four to six calcareous layers about 



the nucleus ; and sometimes there are two nuclei 

 thus enclosed, and then the corpuscles have ex- 

 actly the aspect of the precious stones of Imatra. 



Those of Taenia cucumerina, Bothriocephalus 

 solidus, and Cysticercus fasciolaris, are usually 

 of an oval form, sometimes irregular, and of a 

 variable size. Tschudi (Die Blasenwürmer, 1837, 

 p. 24, Taf. II. fig. 21) has figured those of the last 

 species as eggs. 



1 I have easily seen these muscular fibres in the 

 caudal vesicle of Cysticercus cellulosae, and 

 tenuicollis. But they are wholly absent in the 

 parent-vesicle of Echinococcus hominis, and vete- 

 rinorum. This vesicle, therefore, has probably 

 no spontaneous movements, whilst the embryos it 

 contains at certain times have distinct locomotive 

 organs. 



2 The longitudinal fibres of the subcutaneou« 

 muscular layer, have been observed in Bothrio- 

 cephalus latus, by Eschricht (loc. cit. p. 5.5) 

 and in Taenia angulata, lanceolata, nasuta, and 

 villosa, by myself. 



3 The reticulated muscular parenchyma of the 

 Trematodes {Amphistomum sisanteum) has been 

 represented by Diesing very beautifully (Ann. d. 

 Wiener Museums I. Abth. 2, Taf XXII. fig. 4-S). 



4 In Ascaris lumbricoides, as m most Nema- 

 todes, the muscular fibres are so closely approxi- 

 mated that the meshes of their net-work are not 

 seen except by tearing asunder the muscles ; see 

 Bojanus, Isis 1821, Taf. III. fig. 48. The reticu- 

 lated form of the longitudinal muscles is very dis- 

 tinct in Cheiracanthus gracilis ; see Diesing, 

 Annal. d. Wiener Museums, II. lift. 2, p. 225, Taf. 

 XVII. tig. 1, 2. 



