188 



THE ORGANIZATION 



Unlike that of the Starfish, the organization of Caudina, as 

 this is called, is best understood when seen in profile ; and I will 

 therefore describe it from this point of view, (fig. 114,) and then 

 compare its foreshortened aspect (fig. 115) with that of the Star- 



O A or 8 



/ 



Fig. 116. 



fish. The outline of this animal, as you see by the illustration 

 before you, is that of a thick, worm-shaped figure, of which one 

 end, the head, is rather abruptly terminated, as if cut straight 



branches; m, the madreporic body; me, the madreporic canal; r, the aquiferous 

 ring: aq, the aquiferous canals going from r to the space (aqi) at the base of 

 the feelers (/) ; aq\, aq 2 , aq 1 , aq 5 . aq 6 , aql, the longitudinal aquiferous canals 

 running close to the under surface of the skin; h, 7t>, the heart; c, the ribbon- 

 like nervous collar ; ov, ov 1 , ou 2 , the reproductive organ ; o, the external aper- 

 ture of ov. Original. 



Fig. 115. A diagramic, foreshortened view of fig. 114. A line drawn through 

 A, B, will represent the median plane of the body, dividing it into right and 

 left; g, the intestine ; rt l , rt~, the respiratory branches; rt, entrance to the respir- 

 atory branches; aq4, aq 8 , aq 9 , the positions of the longitudinal aquiferous canals, 

 and the nervous cords ; m, the homologue of the madreporiform body ; me, the 

 madreporic canal ; h, the heart ; o, the aperture of ov^, ov*, the reproductive or- 

 gan ; nw, ms*,ms*, the pairs of longitudinal, muscular bands; d, the skin. 

 Original. 



Fig. 116. An actual transverse section across the median pair of muscular 

 bands (fig. 115, ms) of Caudina, and the nervous cord and aquiferous canal at 

 that point; magnified 40 diameters, m, m\, the edges of the muscular bands; 

 b, a narrow, double, muscular band cut across; /,/', the edges of the circular 

 muscular bands which lie immediately beneath the skin (s) ; /a, /3, a sort of 

 fibrous tissue in which//', are imbedded ; s, s, the skin, composed of numerous 

 heterogeneously interwoven fibres ; c, the aquiferous canal which lies in the fur- 

 row between m, m* ; n, the nervous cord lying just beneath the skin, external to 

 the muscular layers, and imbedded in the fibrous tissue (/ 2 ,/ 3 ). Original. 



