LITUOLIDAE — AMMOBACULITES; TROCHAMMINA; CARTERINA. 21 



origin, and the fact that the wall in this species is composed almost 

 entirely of quartz grains shows the selective power of the organism. 

 A considerable amount of bottom sand must be gone over by the 

 animal before a sufficient amount of quartz grains can be obtained 

 for the making of the test. The specimens are very uniform in 

 size, shape, and general characters, and are to be looked for under 

 shallow-water tropical conditions elsewhere. It differs from the 

 species which I have found in the Gulf of Mexico and in the Carib- 

 bean in deeper water. 



Genus CARTERINA H. B. Brady, 1884. 



Rotalia Carter (in part), Ann. Mag. Nat. Hist., ser. 4, vol. 20, 1877, p. 470. 

 Carterina H. B. Brady, Rep. Voy. Challenger, Zoology, vol. 9, 1884, p. 345. — Chapman, 

 The Foraminifera, 1902, p. 152, 



Test rotaliform, biconvex, of numerous chambers, those of the dorsal side 

 all visible, from the ventral side only those of the last-formed coil; umbilicate; 

 wall composed of numerous oval spicular bodies, elongate, rounded, or 

 pointed at the ends; aperture ventral, opening on the umbilicate area. 



This genus is represented by the single species Carterina spiculotesta 

 (Carter). This has been placed with the Lituolidae, although the test 

 is entirely a secreted one and not dependent on the outside bodies 

 for its formation. 



Carterina spiculotesta ( Carter) . 

 (Plate 1, Figure 5.) 



Rotalia spiculotesta Carter, Ann. Mag. Nat. Hist., ser. 4, vol. 20, 1887, p. 470, pi. 16; ser. 



5, vol. 3, 1879, p. 144; ser. 5, vol. 5, 1880, p. 452. 

 Carterina spiculotesta H. B. Brady, Rep. Voy. Challenger, Zoology, vol. 9, 1884, p. 346, pi. 



41, figs. 7 to 10. — Millett, Journ. Roy. Micr. Soc, 1899, p. 365. — Chapman, Joum. 



Linn. Soc, Zool., vol. 28, 1900, p. 184. — Sidebottom, Mem. Proc. Manchester 



Lit. Philos. Soc, 1905, p. 6, pi. 1, fig. 10. — Heron-Allen and Earland, Trans. Linn. 



Soc, Zool., vol. 20, 1915, p. 620. 



Test normally adherent, rotaliform, biconvex, the dorsal side rounded, 

 ventral side slightly rounded, flattened or concave in the central portion, 

 umbilicate, composed of 3 or 4 volutions, the earlier ones regular, the later 

 ones becoming irregular; chambers distinct; walls thin, translucent, composed 

 largely of fusiform calcareous spicules, with a calcareous cement; aperture 

 small, at the umbilical margin of the ventral side of the last-formed chamber, 

 with a slight Hp; color of the central part dark brown, the later-formed 

 portion white. 



Diameter of the Tortugas specimen 0.50 mm. 



This species, which heretofore has been recorded only from the 

 Indo-Pacific region, has occurred as a single specimen from station 

 22, in 6 fathoms. The specimen is referred to this species, and is 

 composed almost entirely of the peculiar fusiform spicules so char- 

 acteristic of this genus. The species seems usually to be attached 

 to Halimeda, and it may be much more common in this region than 

 the single specimen indicated, if it had been looked for under such 

 conditions. 



