THE BLACK SAND -WORM. 87 



Specks of opaque white ; these organs are usually 

 much spread horizontally, with their tips often curled 

 inward. Another remarkable peculiarity of this spe- 

 cies, is the degree to which it becomes transparent, 

 by distension with water. The effect of this is not 

 the general swelling of the body as in A. crassicornis, 

 which is remarkable for the same habit effected in 

 another way, but the great dilatation of the disk and 

 tentacles, which then expand to an extraordinary 

 degree, both becoming so diaphanous as to be almost 

 destitute of colour, and showing with absolute clear- 

 ness the convoluted filaments within the septal divi- 

 sions of the interior. 



The third variety I have alluded to, is principally 

 found in deep water, though I have obtained one or 

 two remarkably large examples of it on Byng Cliff 

 Ledge. It is larger in size, and coarser in appearance 

 than the other kinds, and is always tinged with a 

 bluish-grey or livid-green hue, though the character- 

 istic marks and habits are always to be recognised. 

 It is fond of taking up its abode within the angular 

 cells or chambers of Eschara foHacea, which affords 

 a retreat to so many and so various creatures. 



I found beneath a stone another specimen of a 

 worm that seems to be uncommon, but which I have 

 met with also near Ilfraoombe, as I have recorded 

 elsewhere, — the Black Sand Worm {Arenicola hran- 

 chialis) ; and a much more elegant animal of the same 

 class, which was new to me, Bigalion hoa ; it bears a 

 general resemblance to the scale-bearing i'o/ywoes, but 

 is drawn out to a much greater lengthy with very nu- 

 merous segments. Crawling in a pool occurred also 



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