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XIX. — Observations on the Shepherd's Purse Coralline oj Ellis, 

 {Notamia bursaria, Fleming). By George Busk, Esq., F.L.S. 



(Read October 27th, 1847). 



Several particulars connected with it, conspire to render the 

 Shepherd's Purse Coralline one of the most interesting subjects of its 

 class. The elegance of its habit, the peculiar conformation of the po- 

 lypidom, and the great comparative transparency of its texture, all 

 invite the attention of the observer. I believe also that the study of 

 this species will, in particular, serve hereafter to throw considerable 

 light upon the structure and functions of those mysterious organs, the 

 " Bird's-head" processes, found upon so many Bryozoa, &c, and with 

 respect to the true nature of which we are as yet so much in the dark. 

 Another point of interest also connected with this species consists in 

 the circumstance that it may in some measure be regarded as a new 

 subject for investigation, for since its original discovery and descrip- 

 tion by Ellis, in 1755, it appears almost to have escaped the notice of 

 naturalists. The description of it given by the Father of Zoophy- 

 tology is still in reality the only one extant ; all subsequent notices 

 having evidently been derived either from that source, or from reference 

 to his figures, and not from actual observation of the creature itself, at 

 all events, in the living state. Neither am I aware, that, with the ex- 

 ception of one or two outline figures, by Dr. Clarke, given in the plate 

 (PI. LI.) of this species in the last edition of Dr. Johnston's valuable 

 work, there has been any addition to, or at least any improvement 

 upon, Ellis's original figure. His description, therefore, and re- 

 presentation, like all those traced by the pen and pencil of that excel- 

 lent observer, though graphic, and as far as his means of observation 

 allowed, correct, will, as may naturally be supposed, admit at the 

 present time of considerable amplification and amendment. The only 

 sufficient reason that can be assigned for the apparent neglect into 

 which this Bryozoon has fallen, is its comparative rarity. Whether 

 this rarity be real or not, I am unable to decide, but I am inclined to 



