NAI1>S. 



[ 51)3 ] 



NASSULA. 



TraiisTorse section of tlie nail and its n.atnx a, matrix- witli its rirlges (Mack); 6, cutis of the lateral folfl : c. 

 r.te n.ucosiun oi tlu- .-ame; </, rete mucosum of the nail with its ridges (white) ; e, enidermic layer of cutaicous 

 told;/, proper .ub.tance of the nail, with short teeth on its under suifaee. <-. ipiatimic lajerol uitaiicous 



Magnified 8 diameters. 



lose their medullary sheath at the level of 

 the corium, and theu run vertically to the 

 surface. 



Fig. 607, 



5*. e 



a 



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 

 rnatrix ; 6. i>lates 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 ; /, nuclei of the 

 ceUs 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. 



Laminae of a nail after boiling with solution of caustic 

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

 membranes ; 6, nuclei seen from above ; e, the same in 

 side view. 



Magnified .350 diameters. 



BiBL. KoUiker, Mik. An. ii. and the Bill. 

 therein ; Biesiadecki, Striclxer''s Hist. 



NAIS, Miill. See NAioiNA. 



NANNOPUS, Brady,— A genus of Cope- 

 podous Entomostraca. (Brady, Cn^). ii.) 



NAR'COTINE. See Alkaloids, p. 31 . 



NAS'SULA, Ehr.— A genus of Holo- 

 trichous Infusoria, of the family Trachelina. 



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 those animals fre- 

 quently contain a coloured liquid, derived 

 from the solution of partly digested Oscilla- 

 torice, 



N. elegans (PI, 31. fig, 45; h, teeth). 

 Length 1-144 to 1-120". 



N. aurea (PI. 31. fig. 4G), Length 1-120". 



