ASSULINA SEMINULUM. 53 



(West, Brown} ; Perthshire (Cash, Brown) ; Argyllshire 

 (Brown); Mid-Lothian (Cash); Dumfriesshire; Wig- 

 townshire (Brown). 



IRULAND. The islands off Clew Bay, and mainland, 

 Mayo; Gal way ; Wicklow (Archer). 



The arrangement of the scales on the fundns of the 

 test is of a more or less radial character (fig. 131), 

 giving place gradually to a diagonal arrangement 

 towards the middle and anterior end of the test ; 

 superficially the scales have the appearance of over- 

 lapping from the fundus downwards, but an examina- 

 tion of the test in section shows that the usual 

 arrangement of the scales holds good, i. e. the anterior 



FIG. 131. Portion of test of Assulina semimtlum. x 1200. 

 Gormire, N. Yorks. 



ones overlap those nearer the apex ; the reverse 

 appearance is probably due to the unusual thickness 

 of the chitinous material which cements them together; 

 owing either to this thickness, or perhaps to an admix- 

 ture of silicious matter with the chitin, the tests are 

 not disintegrated by strong sulphuric acid. 



The pseudopodia are seldom observed, and when the 

 tests are of a brown colour little can be seen of the 

 contents, but the nucleus can usually be located as a 

 light circular patch on which the outlines of the scales 

 are distinguishable. 



Near Lough Nahanagan, Wicklow, 2000 feet, an 

 unusual form occurs; the test is colourless, in broad 

 view narrowly oviform, moderately compressed, of the 

 following dimensions: length about 100 /a; breadth 

 60-65 /x; thickness about two-thirds of the breadth. 



