^102. 



THE HELMINTHES. 



105 



CHAPTER II. 



MUSCULAR SYSTEM AND ORGANS OP LOCOMOTION. 



§ 102. 



The muscular system is well developed with the Helminthes ; 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 oi Botkriocepkalus and TaeniaJ^'' 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 

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

 observation. In the Trematodes, having also an extreme contractility, a 

 large portion of the parenchyma of the body is composed of a muscular 

 reticulated 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 

 all 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. Esckricht (Nov. Act. Acad. Leopold 

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

 not having perceived that they contain carbonate 

 of lime, 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 fViesmanri's Arch. 1841, II. p. 314) has 

 given an exact description of those of Cysticercus, 

 but he also has t;iken them for eggs. In Taenia 

 filum, linea, serrata, and infundihuliformis, 

 they are spherical or oval ; and in the first two 

 species, Goeze (Versuch einer Naturgesch. d. 

 Eingeweidewurmcr, p. 399, 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 cellalosae, 

 Anipisiformis, 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 ov.al form, Sometimes irregular, and of a 

 variable size. Tschudi (Die Blasenwurmer, 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 Itominis, 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 subcutaneous 

 muscular layer, have been observed in Bothrio- 

 cephalus latus, by Esckricht (loc. cit. p. 55) 

 and in Taenia angulata, lanceolata, nasuta, and 

 villosa, by myself. 



3 The reticulated muscular parenchyma of the 

 Trematodes {Amphisturmim gigantcum) has been 

 represented by Diesin:^ very beautifully (\au. d. 

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



4 In Ascaris lumbricoides, as in most Nema- 

 todes, the muscular fibres are so closely approxi- 

 mated that the meshes of then- 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, U. Hft. 2, p. 2i6, laf. 

 XVII. fig. 1, 2. 



