ROTALIIDAE — ROTALIA; HOMOTREMA. 



53 



usually without ornamentation, is the same as that found in the 

 more temperate regions. D'Orbigny does not figure this form in 

 his Cuban monograph. It was not widely distributed in the Tor- 

 tugas region, being found at but three stations, two of them in the 

 moat at Fort Jefferson, in warm, shallow, stagnant water. The 

 other station was on Long Key, under similar conditions. It seems 

 strange that this species, which is so abundant under these conditions, 

 should not occur at any of the stations in deeper water. This would 

 tend to show that this form is perhaps distinct from the ordinary 

 R. heccdrii. 



Genus HOMOTREMA Hickson, 1911. 

 Homotrema rubnun (Lamarck). 



(Plate 14, Figures 6 to 8.) 



Millepora rubra Lamarck, Hist. Nat. Anim. sans Vert., vol. 2, 1816, p. 202. 



Polytrema rubra Dujardin, Hist. Nat. Zooph., 1841, p. 259. — Carpenter, Parker, and Jones, 



Introd. Foram., 1862, p. 235, pi. 13, figs. 18 to 20. 

 Homotrema rubrum Hickson, Trans. Linn. Soc. London, Zoology, ser. 2, vol. 14, 1911, pp. 



445, 454, pi. 30, fig. 2, pi. 31, fig. 9; pi. 32, figs. 19, 22, 28.— Heron-Allen and 



Earland, Trans. Zool. Soc. London, vol. 20, 1915, p. 729.— Cushman, Bull. 100, 



U. S. Nat. Mus., vol. 4, 1921, p. 364. 



At one of the extreme low tides, when the 

 old, dead reefs near Long Key were exposed, 

 it was found that the under sides of most of 



li 



,^^ 



Figs. 4 to 6. — Homotrema rubrum, (Lamarck). 



4. A raised portion, showing the plates and the long, 

 projecting lines of spicules. 



5. A more enlarged view of a younger portion, show- 

 ing the relation of the plates. 



|[6. A portion of one of the lines of spicules with the 

 f''. cementing substance in black. 

 da. A portion of the same, enlarged, showing the 

 areas of cement in stipple. 



