260 NATUEAL HISTORY OP 



L. tetragona (Eeuss, Manzoni), Reptoporina tetragona 

 (D'Orb.), Escliarina variabilis (Leidy). 



Hab.: Ayrshire {D. L.), Cornwall (C. W. P.), 

 Hastings {Miss Jelly), The Minch (A. M. N.), Cornwall, 

 Ilfracombe, Filey (T. H.). 



Two distinct forms of this species are recognized, 

 namely unicoo'nis and ansata. In the former the cells 

 are very distinct and somewhat rectangular, with a 

 small orifice, below which is a pointed mucro. On 

 one or both sides is an aviculaiium. The ooecia are 

 scallop-shaped, with grooved radiations. In the latter 

 form, which "represents the deep-water condition of 

 the species," the cells are broad and squarish, and the 

 ooecia are small and without ornament. Dr. Johnston 

 describes the avicularia as " auricles," and says that 

 " when viewed in front they have a miniature resem- 

 blance to the ears of a fox or a cat." 



2. S. SPINIPERA, Johnston. 



Lepralia ciliata (Hassall), Mollia vulgaris forma 

 spinifera {Smitt), Lepralia spinifera {G.J.,Bush,McA., 

 T. H., Heller, in part). 



Hab.: Shetland {A. M. K), St. Andrews (McL), 

 Wick {G. W. P.), Llandudno, Ilfracombe, &c. {T. E.), 

 Hastings [Miss Jelly). 



Resembles M. ciliata, but has the orifice more 

 rounded, with a semicircular snip out of the lower 

 margin. The cells are generally smooth or only 

 slightly punctured. There are 4 — 6 spines upon the 

 upper half of the aperture, and there is a long spine 

 on the cell a little below the aperture, often with an 

 avicularium in a line with it on the front of the cell. 

 This long spine is inserted in a boss or circular tubercle. 

 Sometimes there are two of these long spines, one 



