LITUOLIDAE 8i 



volution. The final chamber is produced at a tangent to the spiral and terminates in a 

 flattened nipple with slit-shaped aperture. Umbilical region depressed on both sides, 

 marking the area of the inner convolutions. The chambers of the last convolution are 

 sHghtly inflated and do not extend to the edge of the test, which is thus furnished with 

 a solid carina having a rounded peripheral edge. The sutural lines are generally 

 obscure. Colour light grey, surface rough and unpolished. Walls constructed either of 

 fine sand and mud with a considerable proportion of grey cement, or of mud without 

 apparent cement, according to the environment. When sand grains are employed they are 

 generally minute and of uniform size, but whether sand or mud is used, symmetrical 

 construction is often spoiled by the inclusion of one or two large grains. The nipple-like 

 terminal of the final chamber is more neatly constructed than the rest of the shell. 



The characteristic terminal chamber presumably marks the completion of growth, as 

 it is only found in the largest specimens. For this reason, coupled with the fragility of 

 the test, specimens exhibiting this feature are rare. Broken and immature specimens are 

 of frequent occurrence, and in this condition the species closely resembles Ammobacii- 

 lites americmms, Cushman (= Haplophragmium fontinense, Brady hoh Terquem), to 

 which our species is probably closely allied. 



Dimensions. Length of perfect specimens 2-0-2-4 mm.; breadth 1-4-1 -6 mm. 



The species is very generally distributed but is never so common in occurrence as 

 A. amerkamis. The best stations for the mud-building form are Sts. 45, 126 and 149; 

 for the sandy form St. 27. At St. 660 and MS 68 both mud and sand-building forms 

 occur in considerable numbers and attain large dimensions. 



120. Ammobaculites tenuimargo (Brady). 



Haplophragmium tenuimargo, Brady, 1882, FKE, xi, p. 715; 1884, FC, p. 303, pi. xxxiii, figs. 



13-16. 



Haplopliragmium tenuimargo, Flint, 1899, RFA, p. 275, pi. xix, fig. 3. 



Ammobaculites tenuimargo, Cushman, 1918, etc., FAO, 1920, p. 65, pi. xiii, figs. 3-5. 



Four stations: 27, 144, 148; WS 429. 



Always very rare. The best and most typical specimen was found at WS 429 at a 

 depth of 2549 m. More numerous at St. 144. All the specimens except the single one 

 found at WS 429 are very broad in the spiral portion as compared with Brady's figure, 

 suggesting a close relationship with A. americanus. 



121. Ammobaculites foliaceus (Brady). 



Haplophragmium foliaceum, Brady, 1879, etc., RRC, 1881, p. 50; 1884, FC, p. 304, pi. xxxiii, 



figs. 20-5. 



Ammobaculites foliaceus, Cushman, 1918, etc., FAO, 1920, p. 64, pi. xiii, figs, i, 2. 



Three stations: 151 ; WS 63, 334. 



Rare at WS 334 and very rare at St. 151 and WS 63. All the specimens are small and 

 less neatly constructed than usual. 



