3 62 



THE ANIMAL PARASITES OF MAN 



recent investigators, however, state that such a cavity does not exist, 

 but that the space between the longitudinal muscles or their proto- 

 plasmic portions and the gut epithelium is filled by a complicated 

 "isolation tissue." This in the main proceeds from a large cell (/.s\, 

 fig. 262) which lies directly behind the nerve ring dorsal to the 

 oesophagus, and consists of a system of lamellae which sheathe the 

 muscles and penetrate through them to the cutis and also cover the 

 gut in a thin layer. 



We may now consider the " tuft-like " or " phagocytic " organs, 

 which attain i cm. in size, and consist of four, six, or even more 

 ramified cells, which lie close to the walls of the body (fig. 261). 



FIG. 260. Diagram of a transverse section of Ascaris 

 lumbricoides, showing thick cuticle, and beneath it the 

 matrix or syncytial ectoderm. The flat intestine is in 

 the middle, and to the right and left near it in the body 

 wall the lateral lines with excretory vessel and lateral 

 nerves; above and below in the centre the dorsal or 

 ventral median lines with the nerves radiating to the 

 muscles, also the muscle cells with their striated outer 

 contractile portion and inner nucleated vesicular proto- 

 plasmic portion. About 50/1. (After Brandes.) 



FiG. 261. Anterior 

 end of an Ascaris megalo- 

 cephala cut open and 

 showing the four tuft- 

 like organs lying on the 

 lateral lines. Natural size. 

 (After Nassonow.) 



They are found either only in the anterior part of the body (Ascaris), 

 or throughout the whole length of the body (Strongylus, syn. ; Sclero- 

 stomum), and their position usually corresponds to the lateral lines. 

 In some species there are small protoplasmic cells on the processes 

 of these organs. In consequence of their size they can be recognized 

 with the naked eye, especially when they are loaded with granules of 

 stain (carmine, Indian ink) injected into the body cavity. 



