892 Transactions of the Socieiij. 



A. pr/vlatus sp. n. 



Elongately elliptical or suboval, major axis 0'125 to 0"15 mm., 

 from l.\ to 1| times minor. Surface rising gently from central space 

 to processes, transverse median areas distinct, their outer ends rounded 

 at about ;!/4 of radius from centre, outside of this the slope to border 

 gentle. Colour pale grey, darker towards centre. Central space 

 rounded, 0'015 mm. broad. IMarkings, distinct strife with clear 

 interspaces, those converging to the processes uniformly curved but 

 replaced close to the processes by short delicate strife 8 in '01 mm. ; 

 most crowded on the transverse median area, beyond this straight, in 

 direction of axis of this area, elsewhere convex towards processes, at 

 border and near the processes more pruinose, often interrupted or 

 represented by irregular scattered granules ; apiculi inconspicuous, 

 chiefly on transverse median areas. Trocesses 2, large, roundly 

 elliptical, major axis oblique, • 03 mm. long, border finely striated. 



Habitat: Peruvian guano (llae ! Griffin I) ; J'isagua (Kitton !*) ; 

 Islay, Peru (Griffin I) ; Mejillones, Bolivia (Firth !). 



A. caribeeus Cleve, Sch. Atl., pi. Ixvii. figs. 9, 10. 



Subcireular, diam. about 0'05 mm. Surface with indistinctly 

 defined transverse median areas, processes low. Colour ? Central 

 space circular, distinct, about • O075 mm. broad. Markings punctate 

 and irregular, but distinct on transverse areas, strife converging to 

 the processes inconspicuous, beyond the central areas radial and 

 straight to border. Processes rounded, about 0*013 mm. broad, with 

 broad border. 



Habitat : Darien (Schmidt). 



A. macraeanus Grev., Trans. Mic. Soc. Lond., 1863, p. 51, pi. iii. 



fig. 18. 



Circular or roundly elliptical, major axis 0"0625 to 0"115 mm., 

 about Ij times minor. Surface rising slightly from the centre to 

 processes, elsewhere almost flat, transverse median areas short, indis- 

 tinct. Colour pale grey. Central space circular, • 005 to ■ 01 mm. 

 broad. Markings delicate striae, those converging to the processes 

 most evident, elsewhere radial and diverging ; apiculi sometimes 

 evident on transverse areas, and on a narrow band close to border. 

 Processes 2, large, about 0"0325 mm. broad, circular. — Sch. Atl., 

 pi. xxxi. fig. 5. 



Habitat: Ceylon (Macrae!); Oamaru (Rao!); Ashley Paver, 

 North America (Weissflog !). 



A. Grevillei Jan., Abh. Schl. Ges. vater. Cult., 1861, p. 163, pi. ii. 



fig. 11. 



Elliptical, rarely oval, major axis from 0'12 to 0'165 mm., about 

 l^ to 1| times minor. Surface rising slightly from centre to processes, 



* In the Collection of Dr. Griffin. 



