164 Introduction to A nimal Morphology. 



acicular papillae ; no head fissures. The larvce are provided 

 with eyes, which are usually absent in the adults. 



2. Enopla nerve ganglia nearly double; globular, lateral 

 nerve trunks within proper muscular walls ; mouth in front of 

 the nerve commisures, ventral ; no metamorphoses. This in- 

 cludes one family, Amphiporidoe, with two muscular coats 

 only, an outer circular and an inner longitudinal, a prol 

 of three parts, anterior or basal, with seven coats, middle 

 armed with the stylets, and posterior saccular, with two mus- 

 cular coats. Tin- bodies arc generally short, with a long pro- 

 boscis, except in NYmertes. There are three blood-\t 

 and two cephalic arrli 



Rhamphogordius (Rathkc} a thread-like, dioecious or 

 monoecious, jointed worm, with only longitudinal fibres and 

 two terminal, proboscis-like lobes, is placed by some among 

 the Knupla, but by Schn<i<Lr is regarded as forming a sub- 

 division of Nematodes under the name Gymnotoma. 



CHAPTER XXIV. 

 CLASS 2. COTYLIDKA (Van Bcncdcn}. 



ENDO- or ecto-parasites (sometimes only temporarily 

 so), with cup-like or irregular suckers formed of pro- 

 s of the muscular lamina of the body wall, covered 

 with skin. They have no body cavity, sometim' 

 intestine, never an anus, and are ciliated in early life, 

 but shed their outer layer. To this variable group 

 belong two orders : 



i. Cestodea (Rudolphi), tape-worms hermaphro- 

 dite, segmented, endo-parasitic, band-like persona \ 

 with no digestive nor vascular system ; nourished by 

 osmose. The first segment (Head, Nurse, Scolex is 



