NAT1CA. 41 



N. marochiensis, Phil., not Chemnitz ; perhaps N. glaucina, 

 Linn., in part, N. maeilenta, Reeve (fig. 13), not Phil., and N. 

 lactea, Marshall, N. intermedia, Phil., N. Poliana, Chiaje, etc. 



N. CATENA, DaCosta. PI. 7, figs. 42-45. 



Shell yellowish brown, with a single band of very short flexu- 

 ous chestnut markings or spots at the suture ; umbilicus open, 

 rather narrow, partly restricted above by the callus. 



Length, 1-5-2 inches. 



Europe. 



Better known under the later name of N. monilifera, Lam. ; 

 but it is doubtful whether this species has been properly identi- 

 fied ; it is certainly the N. monilifera of most authors. 



The animal is yellowish or drab, with a purplish tinge on the 

 upper part, and faintly lineated with brown. The fry are 

 globular, orange- colored and umbilicated ; they assume the 

 purplish brown markings after they are excluded from the 

 leathery band (fig. 44). 



According to Bouchard-Chantereaux the sexual coition lasts 

 many hours. The spawn-envelope consists of a great number 

 of rounded cells, each containing from 12 to 15 fry, which 

 emerge in succession at an interval of two or three days after at 

 least two months of foetal life. The eggs are laid usually in 

 March and April, and the young are produced in May or June. 

 " When just taken, in vigor, and immersed in sea-water, it is 

 scarcely possible to contemplate a more beautiful and interesting- 

 object, with its shell rising as a globular pyramid from its 

 immense circular disk, elegantly marked with fine dark lines on 

 clear drab ground." CLARK. 



It is N. canrena, Maton and Rackett, N. castanea, Lam., N. 

 Nicolii, Forbes, N. helicina, Brocchi, N. glaucina, Fleming and 

 Pennant. N. ampullaria, Lam., has been referred to this 

 species, but the figure of it given b} T Delessert is more like N. 

 her os, Say. The brown variety called castanea by Lamarck, has 

 since been rechristened Yar. Leckenbyi, Marshall. 



N. LARGILLIERTI, Recluz. PL 14, fig. 29. 



Yellowish' brown, rather smooth, inflated, umbilicus narrow, 

 reduced to a mere slit by the reflected callus. 



Length, 32-45 mill. Newfoundland. 



