166 PROCEEDINGS OF THE NATIONAL MUSEUM. VOL. XXXIV. 
evnillatterall (=A. gibbosa Williamson), and (3) thick forms, still 
more inequilateral (=A. rugosa dOrbigny). In the material 
studied there are two well-developed types; one rather small, shin- 
ing, white, nearly equilateral, moderately vaulted, with all the seg- 
ments Paik in the final volution, the other very gibbous, opaque, 
larger than the first, with some Penal Wore around the aperture near 
the margin, with the chambers uniformly curved, and without the 
sinuosity of the smaller types. It is possible that this second form 
represents a new type, but since so much latitude has been granted 
the original A. lessoni I prefer to consider these two types as one 
and refer to the average symmetrical form as A. lessonii and the other 
as the globose variety. The species is unusually abundant in the 
Hawauan dredgings. It was recognized in the following stations of 
the 19 examined: D. 4000, D. 4025, D. 4174, H. 4480, H. 4440, H. 
4476, H. 4508, H. 4566, H. 4567, H. 4579, mil H. 4694. The typieal 
Anes type is abundant at Station 4476. 
Abundant in the tropical waters of the great oceans. It is best Ne 
veloped on bottoms of less than 30 fathoms, and is rare below 400 
fathoms. 
Genus HETEROSTEGINA. 
HETEROSTEGINA DEPRESSA d’Orbigny. 
‘Heterostegina depress@ D’ORBIGNY, Ann. Sci. Nat., VII, 1826, p. 305, pl. 
Xvil, figs. 5—7, modele No. 99. 
Like /Taplostiche, this genus has but a single living representative. 
It is a shallow-water tropical form found around many coral islands. 
But two specimens of this well-known species were obtained at 
Station H. 4566. 
Genus NUMMULITES. 
NUMMULITES CUMINGII Carpenter. 
Amphistegina cumingii CARPENTER, Phil. Trans., 1859, p. 32, pl. v, figs. 13-17. 
The classification of recent Vuwmmulites is to the mind of the writer 
in an entirely unsatisfactory condition. The difficulty has come from 
considering under one species many marked varieties with not only 
more chambering in each volution but also from a difference in vault- 
ing or thickness of contour, which results in altering the entire figure 
of the shell: Under Amphistegina were mentioned several varieties, 
and the same might be done with the Nwmmudlites series. The mul- 
tiplication of chambers, however, is, I think, important and a form 
with twice the segmentation in a given whorl ought not to be re- 
garded as belonging to a species with only one-half as many. 
Again the asymmetry of the test is one of the chief features which 
serve to distinguish the genus Vwmmulites from Amphistegina, and 
even Carpenter later referred the present form to Nummutlites after 
