436 DISCOVERY REPORTS 



402. Nonion pompilioides (Fichtel and Moll). 



Nautilus pompilioides, Fichtel and Moll, 1798, TM, p. 31, pi. ii, figs. a-c. 

 Nonionina pompilioides, Brady, 1884, FC, p. 719, pi. cix, figs. 10, 11. 

 Nonionina pompilioides, Cushman, 1910, etc., FNP, 1914, p. 25, pi. xvii, fig. 2. 



One station: WS 86. 



A single small but typical specimen. 



403. Nonion sloanii (d'Orbigny) (Plate XVI, figs. 7, 8). 



Nonionina sloanii, d'Orbigny, 1839, FC, p. 46, pi. vi, figs. 18 and 18 bis. 

 Nonion sloanii, Cushman, 191S, etc., FAO, 1930, p. 9, pi. iii, figs. 6-8. 



Four stations: WS 80, 83, 99, 225. 



This is not a very satisfactory species. It appears to be merely a form of A'^. grateloupi 

 characterized by greater turgidity and fewer chambers. It is possibly intermediate 

 between N. grateloupi and A^. scapho. Specimens referable to it are infrequent, but a 

 good series was obtained at WS 83 and 225. It is nowhere common. The Type specimen 

 in Paris is much encrusted, but is recognizable, the sutures being comparatively 

 shallow. 



404. Nonion stelligerum (d'Orbigny). 



Nonionina stelligera, d'Orbigny, 1839, FIC, p. 128, pi. iii, figs, i, 2. 



Nonionina stelligera, Brady, 1884, FC, p. 728, pi. cix, figs. 3-5. 



Nonionina stelligera, Heron-Allen and Earland, 1916, FWS, p. 280, pi. xliii, figs. 8-10. 



Seventeen stations: 48, 51, 53, 236, 388; WS 83, 86, 88, 89, 90, 91, 92, 93, 217, 221, 245, 408. 



This is probably the most abundant and characteristic species of the genus, often 

 fairly numerous and better developed and larger than most of the other species. The 

 local type is characterized by six chambers, and appears to be present in two distinct 

 forms which probably represent the megalo- and microspheric stages. The larger form 

 is characterized by chambers rapidly increasing in the degree of inflation, so that the 

 final chamber is very often very greatly swollen. In the smaller form, the shell is 

 compressed throughout its growth. The finest series was found at WS 88, where both 

 forms were observed. The larger form was noted at 48 and WS 93 and 245, the smaller 

 form at WS 89, 90 and 92. The Type is missing in Paris. 



40^. Nonion boueanum (d'Orbigny). 



Nonionina boueana, d'Orbigny, 1846, FFV, p. 108, pi. v, figs. 11, 12. 

 Nonionina boueana, Terrigi, 1889, CP, p. 119, pi. x, fig. 5. 

 Nonionina boueana, Fornasini, 1900, FA, p. 400, fig. 49. 



Two stations: WS 92, 245. 



Excellent specimens at WS 245, identical with the Paris Type, less typical at the other 

 stations. 



