Introduction to Animal Morphology. 177 



of the human liver, about f " long, with bristled and appa- 

 rently puncturated surface; suckers small, close together, with 

 the sex-opening between them. D. Goliath lives in the 

 hepatic duct of Baloenoptera rostrata ; D. Jacksoni in the 

 Indian elephant ; D. clavigerum develops from the Cercaria 

 of Planorbis ; D, clavatum is found in the swordfish ; 

 (/8) intestine not branched ; uterine pouches reaching the 

 end, as D. lanceolatum the elongate fluke of the sheep (fig. 24) ; 

 rarely in Man ; D. crassum and heterophyes also rarely 

 human; D. trigonocephalus in the otter; D, ophthal- 

 mobium found in the eye of a child ; D. echinatum in wading 

 birds ; D. squamula of the polecat ; D. neuronaia has its 

 pupa in the nerves of the haddock : its perfect state (Gas- 

 terostoma gracilescens) in Lophius. 4. Dicyemidae consists 

 of problematical, ovate, immature, microscopic, ciliated 

 forms, found in the venous sinuses of the kidneys of Cepha- 

 lopoda, with oval or cordate head lobes. Planuliform or 

 worm-like larvae develop within them. Several species are 

 known, which may be immature rhabdocoelous Turbellarians, 

 but are most probably Redise of unknown Trematodes ; two 

 clear lateral streaks are probably water-vascular tubes. 



CHAPTER XXVI. 



CLASS 3. — NEMATELMIA [Vogt], 



Cylindrical, unjointed, mostly dioecious, parasitic 

 worms, with usually a distinct body cavity, and a ru- 

 dimental, non-ciliated, water- vascular system ; but no 

 suckers, bristled ambulatory papillae, respiratory, nor 

 circulatory organs. There is no metameral division, 

 but the dermis is often ringed ; the nervous system is 

 often well developed, and the intestine has usually an 

 anus. Development is direct. 



N 



