132 



EPIZOA. 



surface from which nourishment is obtained ; and, within this, 

 rudimentary jaws furnished with strong teeth are visible, adapted, 

 no doubt, to scarify the part upon which the mouth is placed, in 

 order to ensure an adequate supply of food. In the male Aether es, 

 the sucking-bowl possessed by the female does not exist ; the pre- 

 hensile organs being merely four stout articulated extremities, 

 armed at the end with strong prehensile hooks. 



As we might suppose, from the nature of the food upon which 

 this creature lives, the alimentary system is extremely simple. The 

 oesophagus, the course of which is represented by dotted lines in the 

 last figure, terminates in a straight digestive canal (a), which passes 

 through the centre of the abdomen, but no separation between sto- 

 mach and intestine is visible : the entire tube, from the transverse 

 constrictions visible upon its surface, has a sacculated appearance, 

 and is perceptibly dilated towards the centre of the abdominal 

 cavity ; after which it again diminishes in size as it approaches the 

 anal orifice (Z>), situated at the posterior extremity of the body. 



Near the termination of its Fig. 55. 



course, the alimentary canal 

 passes through a loop formed 

 by transverse bands (w, w), and, 

 moreover, seems to be retained 

 in its position by radiating fibres 

 apparently of a ligamentous cha- 

 racter, but which has been de- 

 scribed as representing a biliary 

 apparatus. 



(172.) The muscular system 

 of this animal is far more perfect 

 in its arrangement than in the 

 preceding classes, and the deli- 

 cate fasciculi which move the 

 rudimentary limbs are visible 

 through the transparent integument (fig. 54). In the abdomen, 

 the muscles form longitudinal and transverse bands, which intersect 

 each other at right angles (Jig. 55, d) ; an arrangement not very 

 different from what we have already seen in the rotiferous ani* 

 malcules. 



(173.) The nervous system appears to consist principally of two 

 long filaments (Jig- 55, c), which run beneath the alimentary ca- 

 nal : but it is extremely probable that these communicate with some 



