LAGENIDAE - 159 



Test rather compressed or lenticular, thinnest at the oral end which is somewhat 

 produced and solid. Aperture fissurine, with entosolenian tube attached to one face and 

 extending to the base of the shell. Edge subacute from the oral extremity to the middle 

 of the test, at which point the edge divides for a time to form an "auricle", the con- 

 taining walls of which do not project to any measurable extent above the flat floor. The 

 base of the test between the "auricles" is rounded and sometimes produced to a blunt 

 central point. Surface externally hyaline and polished, but in some lights having a 

 frosted appearance caused apparently by the internal surface being matt. The surface 

 of the flat "auricles" is opaque and granular, so that in side view they appear to be 

 almost white. Size variable: average length 0-3 mm.; breadth 0-25 mm.; thickness 

 0-15 mm. 



This is rather a distinctive form without any very decided affinities. Although the 

 "auricles " suggest relationship with L. auriailata, they are in no sense pockets as in that 

 species, but so superficial that they would be hardly noticeable, if their opacity did not 

 contrast with the otherwise glassy surface of the test. 



In some respects the test has a superficial resemblance to L. revertens (No. 385), but 

 is devoid of the projecting neck and well-marked carinae of that species. It is rare at 

 St. WS 482 ; a single fine specimen at St. 175 ; both stations are in the Bransfield Strait. 



380. Lagena quadralata, Brady (F 230) (SG 237). 

 One station: WS 482. 



A single specimen with six tubulated wings very weakly developed. The inter- 

 mediate striae are by contrast quite strongly marked. 



381. Lagena quadrilatera, sp.n. (Plate VII, figs. 10, 11). 



Lagena quadrangularis, Heron-Allen and Earland {non Brady), 1922, TN, p. 160, no. 353. 



Three stations: 384-6. 



Test fusiform, four-sided, with acute and more or less carinate edges extending into 

 a tapering neck bearing the simple oral aperture, and similarly extended into the bluntly 

 pointed aboral extremity, which is sometimes furnished with a short terminal spine. 

 The four faces of the test are slightly concave in cross-section at any point. Wall thick 

 and smooth, glassy or dull white. 



Length up to 0-50 mm.; breadth and thickness about o-i2 mm. Rare or very rare at 

 all stations. 



This form agrees with a few specimens obtained from very deep water in the Ross 

 Sea by the Terra Nova, which were referred to L. quadrangularis, Brady (B. 1884, 

 FC, p. 483, pi. cxiv, fig. 11). 



L. quadrilatera diff'ers from Brady's species, which was from shallow water in 

 Torres Straits, in the shape of its cross-section, which is a square with concave sides; 

 L. quadrangularis in similar section is a parallelogram with convex sides. It is probable 

 that, in spite of their external similarity, the two species are not zoologically related, 

 L. quadrangidaris being apparently derived from L. quadrata or L. bicarinata, while 

 L. quadrilatera is more likely to be connected with L. gracilis. 



