Miscellaneous. 467 



diate contact with the hypoderm. The nervous system of the Gordii 

 is endowed with very remarkable absorbent properties, which may, 

 under certain conditions, give it the appearance of a true vascular 

 apparatus. Water penetrates into it with the greatest facility, and 

 causes in it singular alterations as soon as the animal loses some of 

 its vitality. The cells of the hypodermic network dilate and become 

 pyriform ; the epidermis of the papillae also swells and becomes 

 prolonged exteriorly in the form of tubes or long filaments. These 

 alterations have been described by Mbbius and Grenacher as normal 

 and integral parts of the animal ; by Yon Siebold and myself as para- 

 sitic Algae. 



The muscular elements of the Gordii are derived from the em- 

 bryonic cell by a series of very simple modifications. The myoblast, 

 by elongation and lateral compression, passes from the spherical form 

 to the ribbon-like state. The envelope of the cell constitutes the 

 myolemma ; and its contents (protoplasm and nucleus confounded 

 together) become converted into contractile substance. The latter 

 condenses against the cell-wall and divides into longitudinal fibrillar 

 parallel to the longer axis of the fibre. The thickness of the mus- 

 cular layer thus increases in the direct ratio of the lateral flattening 

 of the embryonic cells. This process of formation, which is common 

 to the Nematoids, the Gordians, and the Polygordians, attains its 

 maximum of development in the last-named. 



The atrophy of the digestive apparatus consists principally in the 

 disappearance of the mouth and oesophagus. The so-called " secre- 

 tory organ," described by Meissner in the adult Gordii, is nothing 

 but the intestine. Its true nature is attested by the fact that in 

 the larvae it is in relations of continuity with the mouth and oeso- 

 phagus. In the adults we see that it opens posteriorly into the 

 cloaca, and that in front it terminates below the cephalic ganglion in 

 a very slender caecum. The contraction of the anterior extremity 

 of the intestine results both from the degenerescence of its tissues, 

 and from a sort of constriction caused by the connective fibres of 

 the parenchyma. 



The divisions of the cloaca of the female, which Grenacher has 

 designated by the names of seminal receptacle, uterus, and cloaca proper, 

 do not correspond either to differences of structure or to differences 

 of function. 



As to the parenchyma it is constituted by very diverse anatomical 

 elements. Some parts remain, even in the adults, in the state of 

 embryonic tissue ; others pass to the condition of connective or even 

 of cartilaginous tissue. By making transverse sections upon the 

 cloaca of the females, we can see how these different tissues are de- 

 rived from each other ; in fact we can distinguish in them four 

 well-characterized zones ; the most inferior is entirely composed of 

 embryonic cells, not yet modified, but already in course of prolife- 

 ration ; the second zone is formed of cells having all the properties 

 of the cartilaginous cell ; the third zone shows the passage from 

 the cartilaginous cell to the connective corpuscle ; the fourth and 

 last zone is represented by normal connective tissue, such as is 

 observed in most of the inferior animals. — Comptes Mendus, Nov. 8, 

 1880, p. 774. 



