66 BULLETIN: MUSEUM OF COMPARATIVE ZOOLOGY, 
ALLIED ForMS: — 
1. G. sacculifera Brapy. 
G. sacculifera Br. (1879), 1884, Chall. Rep., IX. p. 604, Pl. LXXX. Figs. 11-17, 
Pl. LX XXII. Fig. 4. 
G. bulloides var. Goks, 1882, Ret. Rhizop. Caribb. Sea, Sv. Vet. Ak. Hdl., XIX. 
4, Pl. VI. Figs. 197-200. 
A very variable form. The last segment is sometimes not produced in 
length, but only compressed. Usually the segments are more loosely co- 
herent than in the type. 
Pelagic on both sides of the Isthmus. 
2. G. dubia (Eccer) Brapy. 
G. dubia (Ecenr, 1857) Br. (1879), 1884, Chall. Rep., IX. p. 595, Pl. LXXIX. 
Fig. 17. 
A more regular rotaliform variety, and probably a more developed form 
of G. cretacea D’ORB., with 5-7 inflated segments in the outer convolution 
and a deep umbilical vestibule. 
The stout form seems to have its main abode in the Pacific, while the 
pygmy form (G. cretacea D’ORB.) is prevalent in the Caribbean Sea. 
3. G, equilateralis Brapy. 
G. bulloides var. Gos, 1882, Ret. Rhizop. Caribb. Sea, Sv. Vet. Ak. Hdl., XTX. 
4, Pl. VI. Figs. 201, 202. 
G. cequilateralis Br. (1879), 1884, Chall. Rep., IX. p. 605, Pl. LX XX. Figs.18-21. 
G. equilateralis Gos, 1874, Sv. Vet. Ak. Hdl., XXV. 9, p. 86, Pl. XIV. Fig. 767. 
Mostly planospiral in the arrangement of its few chambers; often the 
last whorl constitutes an open detached spiral, but at other times it is quite 
closely attached to the preceding one. 
On both sides of the Isthmus. Pelagic. 
4. G. conglobata Brapy. 
G. conglobata Br. (1879), 1884, Chall. Rep., IX. p. 608, Pl. LX XX. Figs. 1-5; 
Pl. LXXXII. Fig. 5. 
G. bulloides var. Goiis, 1882, Ret. Rhizop. Caribb. Sea, Sv. Vet. Ak. Hdl. 
XIX. 4, Pl. VI. Fig. 196. 
G. bulloides Goiis, 1894, Sv. Vet. Ak. Hdl., XXV. 9, p. 86, Pl. XIV. Figs. 768, 
769. 
Seems to be a riper form of the type; the arrangement of the chambers 
is subject to some variability ; the sutural apertures of the spire are no 
constant feature. 
Both sides of the Isthmus. 
