ANIMAL PARASITES. 



SECOND GROUP. 



PARASITES WITH DISTINCT TRANSVERSELY STRIATED MUSCULAR 



FIBRES. 



First principal Division ARTICULATA. 



The articulate or jointed animals may be described after 

 C. Vogt. 



Articulata sunt animalia typum bilateralem quoad corporis 

 siructuram sequentia ; symmetricam organorum positionem stride 

 observantia ; organa motoria articulata et ex cams interneque 

 musculosis articulis formata, exhibentia, inque static embryonali 

 vitellum, embryonis medulla abdominali ex diametro oppositum 

 prabentia, ita ut embryo vitellum superficie dorsali tangat. 

 , The Articulata exhibit the following peculiarities : 



1. The greatest symmetry in the arrangement of the lateral and 

 median organs. 



2. A transverse division of the body into several rings or zonites, 

 which in type stand near the Annelidous worms. 



3. A dissimilar segmentation in different regions of the body, 

 which allows us to distinguish, sometimes head, thorax, and 

 abdomen, sometimes only an abdomen and a head and thorax 

 fused together (CephaJothorax, in spiders and crabs), sometimes 

 only a body amalgamated into a single piece (mites). 



4. A knotted nervous cord laid upon the inner wall (not at the 

 back as in the Vertebrata) which forms an oesophageal ring by 



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