EUGLYPHA. O 



and is seen to be divided into three nearly equal zones ; 

 that nearest the aperture is alveolar in structure, the 

 -central zone is granular and contains the greater 

 portion of the food particles and granules of excretion, 

 etc., whilst the third zone, "which occupies the fundus, 

 consists of the clear peri-nuclear plasma. 



The spines with which the tests of most of the 

 species are furnished are very various in shape, but are 

 fundamentally of two kinds only, viz. (1) modified 

 scales, (2) extraneous in character and attached to the 

 test at the imbrications of the scales. As might be 

 expected the scale-spines are fairly constant in their 

 presence and shapes, but species bearing attached 

 spines are frequently glabrous, and the spines when 

 present may vary greatly, not only in number, but 

 also in length and form ; they may also occur in pairs 

 or threes, while scale-spines only occur singly. 



The development of the scale-spines may be traced 

 through a series of species beginning with E. tuber- 

 culata, which is glabrous, except var. cirrata Wailes, 

 found in America, through E. scutigera in which they 

 are rudimentary, and J/, aspera in which they are short 

 and thorn-like, to E. acanthopJiora in which they 

 are fully developed. In E. hrachiata they are highly 

 specialised and in E. cristata and E. h'ljophila they are 

 confined to apical tufts. For purposes of classification 

 the spines may be differentiated as f oUoavs : — 



(1) Modified scales. 



(2) Attached to the test at the imbrications of the 

 scales, and may^ — 



(a) Arise direct as fine cils {E. ciliata and E. 

 strigosa) ; 



(6) Be attached by small hemispherical nodules at 

 their bases and be acicular {E. filifera) or dagger- 

 shaped {E. compressa). 



The shape of the body-scales iii this genus varies 

 from elliptical to circular except in three species, which 

 possess scutiform scales, viz. — E. scutigera Penard, E. 

 aspera Penard, and E. crenuiata Wailes. 



