20 SHALLOW-WATER FORAMINIFKRA OF TORTUGAS REGION. 



FamUy LITUOLIDiE. 



Genus AMMOBACULITES Cushman, 1910. 



Ammobaculites reophacifonnis Cushman. 



(Plate 1, Figure 1.) 



Haplcphragmium aonlutinans H. B. Brady (part, not d'Orbigny), Rep. Voy. Challengtr, 

 Zoolojo'. vol. 9. 1884, pi. 32, fig. 22 (not 19 to 21, 23 to 36). 



Ammobaculites reophaciformis Cushman, Proc. U. S. Nat. Mu8., vol. 38, 1910, p. 440; Bull. 

 104, U. S. Nat. Mu8., pt. 2. 1920, p. 67, pi. 13, fig. 6; Proc. U. S. Nat. Mua., vol. 

 59, 1921. p. 49. 



Test elongate, tapering, early portion consisting of a few chambers 

 planospirally coiled and much compressed, making up but a small portion of 

 the test, later and by far the larger part uncoiled, forming a straight linear 

 series, circular in transverse section, and progressively increasing in size, the 

 last-formed one being the largest; chambers fairly distinct; sutures slightly 

 depressed; wall composed of angular fragments, smoothly finished; aperture 

 circular, terminal, simple, occasionally with a slight neck ; color usually white 

 or gray. 



Length of the Tortugas specimens hardly more than 1 mm. 



This species, which might be expected to be fairly common in 

 this shallow- water coral-reef region, has been found to be surpris- 

 ingly rare here. Single specimens were obtained at only 2 of the 

 20 stations. This seems all the more noteworthj'-, as it occurs at a 

 number of stations in the West Indies, and such conditions as prevail 

 in the Tortugas region would seem to be ideal for its development. 



The specimen figured is very typical, showing the early coiled 

 portion and the more or less pyriform chambers of the uncoiled 

 part, gradually increasing in size toward the end. The only figure 

 referred to above from the Challenger Report seems to represent 

 this species, which should not be confused with Ammobaculites 

 agglutinans (d'Orbigny). 



The species is known also from the Hawaiian Islands and westward 

 across the Pacific, at least to the Philippine region. 



Genus TROCHAMMINA Parker and Jones, 1860. 



Trochaminina advena, new species. 



(Plate 1, Figures 2 to 4.) 



Test small, composed of about 2.5 volutions, unequally biconvex, the 

 dorsal side much more flattened than the ventral, the final whorl composed of 

 4 chambers, more or less inflated; sutures slightly depressed; wall composed 

 of sand-grains, apparently of quartz, with a considerable amount of light 

 grayish cement; the surface rather smooth, whole test umbihcate below; the 

 aperture at the inner margin of the final chamber short, rounded, with a 

 very slight overhanging lip; color gray. 



Diameter up to 0.45 mm. 



The three stations from which specimens were obtained are all 

 within the lagoon, and range from 4.75 to 10.5 fathoms. The 

 bottom in all three stations is a fine white sand, mostly of calcareous 



