NAILS. 



[ 533 ] 



NASSULA, 



Transverse section of the nail and its matrix, a, matrix with its ridges (black) ; 6, cutis of the lateral fold e, 

 rete mucosum of the same; d, rete mucosum of the nail with its ridges (white) ; e, epidermic layer of cutaneous 

 fold; f, proper substance of the nail, with short teeth on its under burface. 



Magnified 8 diameters. 



lose their medullary sheath at the level of 

 the corium, and then run vertically to the 

 surface. 



Fig. 607. 



Transverse section of the body of the nail. A, cutis 

 of the matrix.- B, rete mucosum of the nail. C, epi- 

 dermis of the same, or proper nail, a, plates of the 

 matrix; 6, plates of the rete mucosum of the nail; c, 

 ridges of the proper substance of the nail ; d, deeper 

 perpendicular cells of the rete mucosum of the nail ; 

 e, upper flattened cells of the same ; f, nuclei of the 

 cells of the proper nail. 



Magnified 250 diameters. 



The cutaneous epidermis (fig. 506 e) ex- 

 tends for a certain distance into the lateral 

 and posterior depressions of the skin, covers 

 the anterior portion of the root, the poste- 

 rior part of the "body, and the lateral mar- 

 gins of the nails, terminating in a fine layer 

 which, however, is nowhere directly con- 

 tinuous with the substance of the nail. 



Laminse of a nail after boiling with solution of caustic 

 soda or potash. A, side view. B, surface view, a, cell- 

 membranes ; b, nuclei seen from above ; c, the same in 

 side view. 



Magnified 350 diameters. 



BIBL. Kolliker, Mik. An. ii. and the JBibl. 

 therein ; Biesiadecki, Strickw's Hist. 



NAIS, Mull. See NAIDINA. 



NANNOPUS, Brady. A genus of Cope- 

 podous Entornostraca. (Brady, Cop. ii.) 



N AB/COTINE. See ALKALOIDS, p. 31 . 



NAS'SULA, Ehr. A genus of Holo- 

 trichous Infusoria, of the family Trachelma. 



Char. Body covered with cilia arranged 

 in longitudinal rows; mouth surrounded by 

 a cone of rod-like teeth ; no proboscis nor 

 ear-like processes. 



The gastric sacculi of these animals fre- 

 quently contain a coloured liquid, derived 

 from the solution of partly digested Oscilla- 

 torice. 



N. elegans (PL 31. fig. 45; b, teeth). 

 Length 1-144 to 1-120". 



N. aurea (PL 31. fig. 46). Length 1-120". 



