658 FASCICLES. 



ole enclosed within the anterior lateral petals, extending across the abactinal 

 extremity of the posterior poriferous zone of the posterior lateral ambulacra, 

 and running parallel to the odd ambulacrum, crossing it at some distance 

 above the ambitus. This internal fasciole takes the place of the peripetalous 

 fasciole, but in Breynia both occur together. The use of these bands of em- 

 bryonic spines is evidently to keep the petals free from foreign matters. We 

 always find along the fascioles large accumulations of dirt, which are laid 

 there by the minute spines as by a sieve. Troschel first called attention tu 

 the true nature of the appendages of the fascioles ; Midler subsequently, in 

 his Embryology of the Echinoderms, gave excellent figures of the spines of 

 the fascioles of Schizaster ; yet, in spite of these observations, dating back to 

 1852, recent writers persist in stating that the fascioles carry true pedicel- 

 lariae, while in all Spatangoids pedicellariae are found scattered over the 

 whole test, but they are especially numerous round the actinostome and 

 along the bare ambulacral actinal avenues. 



Liitken has attempted, from the arrangement and combination of the fasci- 

 oles, — their presence or absence, — to make a classification of the Spatan- 

 goids. As he himself says, it is a most artificial one, and one which can only 

 be used as an auxiliary with other features ; the subanal, anal, and lateral 

 fascioles are subject to great changes during growth, and to considerable 

 variations in older specimens. The peripetalous and the internal fascioles 

 offer more constant characters. 



