ROTALIIDAE — TRETOMPHALUS; PLANORBULI^A. 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, pi. 

 92, fig. 4. — H. B. Brady, Parker, and Jones, Trans. Zool. Soc. London, vol. 12, 

 1888, p. 227, pi. 46, fig. 11.— Flint, Rep. U. S. Nat. Mus., 1897 (1899), p. 328. pi. 

 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, pi. 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, pi. 14, fig. 1; fig. 32 (in text); Proc. U. S. 

 Nat. Mus., vol. 59, 1921, p. 55, pi. 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 acervuUne 

 chambers; wall conspicuously porous; apertures Upped. 



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 Id 

 quantity in shallow w^ater in protected places. 



Planorbulina mediterranensis d'Orbigny. 



(Plate 6, Figures 1, 2.) 



Planorbulina mediterranensis d'Orbigny, Ann. Sci. Nat., vol. 7, 1826, p. 280, pi. 14, figs. 

 4 to 6; Modeles, 1826, No. 79; Foram. Foss. Bass. Tert. Vienne, 1846, p. 166, 

 pi. 9, figs. 15 to 17.— H. B. Brady, Rep. Voy. Challenger, Zoology, vol. 9, 1884, 

 p. 656, pi. 92, figs. 1 to 3. — H. B. Brady, Parker, and Jones, Trans. Zool. Soo. 

 London, vol. 12, 1888, p. 227, pi. 45, fig. 18.— Sidebottom, Mem. Proc. Manches- 

 ter Lit. Philos. Soc, vol. 53, 1909, p. l,pl. l,figs. 1-3; vol. 54, No. 16, 1910, p. 26.— 

 Cushman, Bull. 71, U. S. Nat. Mus., pt. 5, 1915, p. 28, pi. 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. 



