LAGENINAE 373 



Fissurina alata, Reuss, 1851, has a pronounced carina being intermediate between 

 Lagena laevigata and L. marginata. Fissurina globosa, Bornemann, 1855, is merely an 

 inflated form of F. laevigata and the two can be connected by intermediate variations. 

 It might have been accepted as an alternative. But again priority of publication in- 

 tervenes, Bornemann 's specific name having been used much earlier by Montagu (see 

 No. 169). 



Seguenza (S. 1862, FMMM) figured and described a long series of fissurine Lagenae, 

 many of which are but forms oi Lagena laevigata (Reuss), an extremely variable species. 

 It appears therefore to be a case of selecting the earliest suitable specific name from his 

 monograph. The first two species Fissurina solida and F. riigosula may be disregarded. 

 They are too inflated for our purpose, and the surface of the test is described as rather 

 rough, or rough, though the figures do not convey that impression to any extent. The 

 next species Fissurina simplex would be very suitable for our requirements, but again 

 priority intervenes, both Reuss (1851) and Terquem and BertheUn (1862) having used 

 the specific name for two distinct forms. Fissurina deltoidea and F. latistoma which 

 follow do not conform to requirements, but the sixth species Fissurina biancae bears a 

 close resemblance, both in figure and description, to Fissurina laevigata, Reuss, and we 

 have accordingly selected it to supersede that species. 



Universally distributed and often very abundant. At WS 83, it exhibits practically 

 all the variations found elsewhere in the area. Besides the typical Reuss form there are 

 others, notably a strongly punctate form. Such punctation is one of the most constant 

 features of the species in the Falkland area. This particular form, which is very variable 

 in size, good specimens averaging 0-30 mm. in length, 0-25 in breadth, presents two 

 sub-variations ; in the first, the punctation is uniform all over the shell, in the second it is 

 confined to the marginal area, the central area being hyaline and clear. Another variety 

 is characterized by a limited number of much coarser perforations which may either be 

 irregularly disposed, or arranged in lines upon the surface. The marginal edge varies 

 enormously, from the acute angle of the type to a narrow, sharply produced keel in the 

 one direction, and, in the other, to a bluntly rounded edge. A small variety common at 

 WS 83 and occurring at several others is characterized by a roughly "matt" surface not 

 due to the decomposition of the shell. 



The aperture is normally fissurine, but hooded specimens, otherwise absolutely 

 identical with the fissurine, are found here and at several other stations. A remarkably 

 fine trigonal specimen was found at WS 83 (Plate X, fig. 39). 



211. Lagena acuta (Reuss). 



Fissurina acuta, Reuss, 1858, FP, p. 434; 1862, FFL, p. 340, pi. vii, figs. 90, 91. 

 Lagena acuta, Cushman, 1910, etc., FNP, 1913, p. 6, pi. xxxviii, fig. 6. 



Thirteen stations: 48; WS 71, 76, 80, 83, 86, 87, 88, 90, 92, 210, 245, 248. 



Fissurine Lagenae with pointed bases occur rarely at many of the stations, but no very 

 typical specimens were found. The best were at WS 88 and 210. At WS 83, a specimen 

 was seen with two basal spines. 



