Anatomy and Affinities 0/ Hypsobia nosopliora. 405 



confined than in tliose forms. The paractenidial folds differ 

 from the above in havin<^- no expanded ciliated portion. 

 Otherwise they do not differ from the true gill. The lacunar 

 system is continuous from the filaments into the paractenidial 

 folds (fi-. 2). 



The afferent vessels are derivatives of an irregular lacunar 

 system communicating witii the ample rectal sinus. 



Fig.2. 



H. nosophora. 



Horizontal section through base of gill-Limellse {(j) and paractenidial 

 filaments (^j). 



All that is known of the habits of this animal points to its 

 being amphibious. Heude says of the Chinese species tiiat 

 it does not live in water, but on damp rocks. No such details 

 of the actualjuode of life of the Japanese species are available ; 

 but Cort (4) has shown that it will leave the water voluntarily 

 and can resist dessication for about three mouths. 



III. Renal System. 



The Icldney is rather remarkable among the Palxidestrina- 

 like forms on account of its complexity. In all the specimens 

 examined it was possible to distinguish three areas, which 

 we!-e, however, by no means constant in their distribution or 

 histological condition. 



1. Trabecular Portion. — This consists of a number of 



cavities separated by a trabecular system covered by 

 the same type of epithelium as the open portion of the 

 kidney. In the walls of these cavities are found 

 numerous blood-spaces (iig. 3). 



2. The '■'' blood-gland^'' is a compact stroma usually l}ii)g 



near the renal aperture at the anterior end and on the 

 outer side of the kidney next to the body-w:ill. 



