BULLETIN: MUSEUM OF COMPARATIVE ZOOLOGY. 
always met with which are not provided with keels on the two segments pre- 
ceding the two last ones. 
Caribbean Sea. 300-800 fathoms; not plenty. 
ALLIED Forms: 一 
1. M. procera Goiis. Plate VII. Figs. 7-9. 
This is a short inflated variety of seminulum. The aperture is usually 
an undulating irregular slit, like that in certain forms of Biloculina. Some- 
times a faint longitudinal striation on the antepenultima segment is dis- 
coverable. It seems to be closely allied to M. circularis (BORNEM.) BR., 
the chief difference being its quinqueloculine arrangement of the chambers, 
Besides, it may be identical with the inflated forms exhibited by Borne- 
mann as Quinqueloc. ovalis and cognata from Septaria clay, and impressa 
and regularis Reuss, all forms which can hardly be distinguished from. 
circularis except by their quinqueloculine structure, Length 2.40 mm, 
Pacific. 885 fathoms ; scarce. 
Caribbean Sea, 885 fathoms; not common, 
2. M. circularis Bornem. 
Triloculina circularis Bornem., 1855, Sept. Thon Hermsdorf, Zeitschr. deut. 
geol. Gesellsch., VII. p. 349, "E XIX. Fig. 4. 
Mil. circularis Br., 1884, Chall. Rep., IX. p. 169, Pl. IV. Fig. 8. 
An ill defined form, with usually inflated segments in a triloculine 
arrangement, and a crescentic or somewhat angular mouth. It has often a 
longitudinal impression on both sides of the antepenultima segment, but 
this feature is not at all constant. 
Pacific. 885 fathoms; scarce. 
Caribbean Sea. 978 fathoms; scarce. 
3. M. contorta »'Onn, var. Plate VIT. Figs. 10-12; Plate VIII. Figs. 1-7. 
Quinqueloc. contorta D'ORB., 1846, Bass. tert. Vienne, p. 298, Pl, XX. Figs. 4-6. 
pa n annectens, rugosa SCHLUMB., 1893, Mém. Soc. Zool. Fr., VI. PI, III. 
Figs. 77-79, Pl. IV. Figs. 91-93. 
Mil. contorta Goiis, 1894, Arct. & Scand. Foramf., Sv. Vet. Ak. Hdl., XXV. 9, 
p. 111, Pl. XX. Figs. 851, 852. 
In his memoir on Fossil Foraminifere of the tertiarian basin at Vienna, 
d'Orbigny has described and designed a set of Quinqueloculine character- 
ized principally by their truncate or hollowed margin of the two last 
segments and the more or less angular projection of the two or three pre- 
ceding ones. The most of those forms are too closely allied to be ranked. 
as species, and. the small differences are too fickle to entitle them even 
to varietal denomination. 
With more or less reason some authors have reunited some of these 
forms under d’Orbigny’s Quinqueloc, Ferusacti, seemingly a thinnev form, 
but with the same leading features as the Vienna forms. In the mean time 
