286 ALLAN HANCOCK PACIFIC EXPEDITIONS VOL. 6 



"Test generally triangular in section, initial end bluntly rounded, 

 chambers few, distinct, the three sides flattened, the angles with sharp 

 carinae often with fine radial tubules, sutures distinct, depressed; wall 

 smooth, thick, opaque; aperture with a very short neck and distinct lip. 

 Length up to 0.90 mm." 



The original description of A. carinata Cushman, quoted above, ac- 

 curately describes a large number of specimens from the following sta- 

 tions: 35, 55, 56, 57, 60, 64, 80, 82, 223, 230, 242, 250, 284, 299, 517, 

 1055, 1069, 1077, 1078, 1081, 1082, 1101, 1103, 1110, 1116, 1118, 

 1120, 1124, 1130, 1137, 1141, 1146, 1157, 1168, 1173, 1177, 1178, 

 1180, 1182, 1183, 1196, 1198, 1199, 1200, 1201, 1205, 1223, 1243, 

 1244, 2000, 2009, 2070, 2079, 2084, 2097, 2098, 2100, 2101, 2106, 

 2107, 2144, 2151, 2152, 2158, 2161, 2162, 2163. It occurs very abun- 

 dantly at stations: 55, 56, 60, 64, 1147, 2101, 2158. 



The species was described from Guide Station 12, Lat. 32° 28' N., 

 Long. 118° 20' W., 429 fms, and has been recorded from other Pacific 

 localities and from the Pliocene, Charco Azul formation, of Panama. 



This species is very distinctive in the white, opaque shell well. The 

 radial tubules in the-carinae of the test are not always present. As noted 

 in the original description, the species attains a large size. The largest 

 observed in the present collection are 1.90 mm in length and 0.70 mm in 

 breadth, from Station 2014. 



In some specimens there is a tendency toward a few large, low costae 

 on the early part of the test and sometimes the carinae are broken into 

 projecting spines at the initial end of the test. In these characters the spe- 

 cies approaches var. vana, n. var. 



In the large collection available, another direction of variation has 

 been noted : toward a more slender, somewhat twisted form with less 

 prominent and blunt carinae. A specimen is figured but the available 

 material is too meager to warrant description as a new variety, figure 11. 

 Specimens occur at stations : 2000, 2009, 2014, 2100, 2101, 2151. 



This species is easily distinguished from A. albatrossi Cushman, with 

 which it occurs, by its carinae which are continuous from initial to aper- 

 tural end, and by its much more regular form with nearly horizontal 

 sutures. 



Distribution. — These stations are off Catalina Island and southward 

 to the coast of Colombia in 116 fms, including many localities in the Gulf 

 of California. The depth range recorded here is 6 to 250 fms. 



