ROTALIIDAE—TRETOMPHALUS; PLANORBULINA. 45 
Genus PLANORBULINA d’Orbigny, 1826. 
Planorbulina acervalis H. B. Brady. 
(Plate 6, Figure 3.) 
Planorbulina acervalis H. B. Brady, Rep. Voy. Challenger, Zoology, vol. 9, 1884, p. 657, pl. 
92, fig. 4-H. B. Brady, Parker, and Jones, Trans. Zool. Soc. London, vol. 12, 
1888, p. 227, pl. 46, fig. 11—Flint, Rep. U. S. Nat. Mus., 1897 (1899), p. 328, pl. 
72, fig. 7.—Millett, Journ. Roy. Micr. Soc., 1904, p. 490.—Rhumbler, Zool. Jahrb., 
Abteil Syst., vol. 24, 1906, p. 67.—Sidebottom, Mem. Proc. Manchester Lit. Phi- 
los. Soc., vol. 53, 1909, p. 2, pl. 1, fig. 4; vol. 54, No. 16, 1910, p. 27.—Heron-Allen 
and Earland, Trans. Zool. Soc. London, vol. 20, 1915, p. 705.—Cushman, Bull. 
71, U. S. Nat. Mus., pt. 5, 1915, p. 29, pl. 14, fig. 1; fig. 32 (in text); Proc. U. 5. 
Nat. Mus., vol. 59, 1921, p. 55, pl. 12, fig. 8. 
Test typically adherent, composed of numerous chambers, early ones 
spiral, later ones irregularly annular, those of the periphery lobulated, the 
newly added chambers extending outward a considerable distance beyond the 
preceding ones; ventral surface often covered by a mass of small acervuline 
chambers; wall conspicuously porous; apertures lipped. 
Diameter of the Tortugas specimens up to 3 mm. 
A discussion of this species as it occurs in the West Indies has 
already been given in the Jamaica paper. Planorbulina acervalis 
seems to be common in the Gulf of Mexico and in the Caribbean. 
Whether or not this is really identical with P. vulgaris d’Orbigny is 
a question which must be left to an examination of the type. There 
is nothing in the Tortugas collection, any more than in that from 
Jamaica, which would seem to belong to vulgaris, unless it is material 
referred to P. acervalis H. B. Brady. There are a few very large 
specimens which have the chambers added on both sides, indicating 
that probably these specimens have become freed from their at- 
tachment and then added chambers on the whole of the exterior of 
the test. Such specimens remind one of Gypsina, but are evidently 
related to P. acervalis. As in Jamaica, P. acervalis is found com- 
monly attached to the short eel-grass (Posidonia), which grows in 
quantity in shallow water in protected places. 
Planorbulina mediterranensis d’Orbigny. 
(Plate 6, Figures 1, 2.) 
Planorbulina mediterranensis d’Orbigny, Ann. Sci. Nat., vol. 7, 1826, p. 280, pl. 14, figs. 
4 to 6; Modéles, 1826, No. 79; Foram. Foss. Bass. Tert. Vienne, 1846, p. 166, 
pl. 9, figs. 15 to 17.—H. B. Brady, Rep. Voy. Challenger, Zoology, vol. 9, 1884, 
p. 656, pl. 92, figs. 1 to 3—H. B. Brady, Parker, and Jones, Trans. Zool. Soc. 
London, vol. 12, 1888, p. 227, pl. 45, fig. 18.—Sidebottom, Mem. Proc. Manches- 
ter Lit. Philos. Soc., vol. 53, 1909, p. 1, pl. 1, figs. 1-3; vol. 54, No. 16, 1910, p. 26.— 
Cushman, Bull. 71, U.S. Nat. Mus., pt. 5, 1915, p. 28, pl. 12, fig. 1; fig. 31 (in text). 
Test adherent, flattened; early chambers distinctly spiral, later ones less 
so, often irregularly annular in their arrangement, more or less lobulated on 
the ventral face; periphery irregular, often angular; wall very conspicuously 
perforated; early chambers usually with a brownish color, later chambers 
grayish white; sutures depressed, often clearly marked on the dorsal face by 
a distinct band of shell material; aperture at either side of the chamber in 
the adult, simple, each with a raised lip. 
Diameter of the Tortugas specimens up to 1 mm. 
