166 ZOOPHYTES 



I 4. Specimens. — Plates XL., XLI. — The following descriptive no- 

 tices are given as a sequel to the preceding observations. They must be 

 taken in a general sense, as requiring verification and further study, toge- 

 ther with the proofs of identity, and various other matters. 



I know not whether all the subjects are actually distinct from those 

 represented and described. But they seem to correspond with the Bo- 

 tryllus or Botryttoides of M. Milne Edwards, whose work did not come 

 into my possession, as already observed, until August 1846, though I can- 

 not presume to identify them with the species named by him. Thus I 

 shall merely allude briefly and generally to such as occurred to myself, 

 which will serve to explain the varieties and the form of the product. 



(1.) It is the nature of the Botryllus, while in the simple ascidian stage, 

 to adhere to some foreign product, which it gradually invests by its in- 

 crease, and almost, or entirely, conceals by the greatest progress of growth. 

 All the subsequent specimens have been originally pendent from 

 marine plants, passing their utmost limits by the course of increment, and 

 then hanging free during adhesion. But part of such plants remain- 

 ing untouched, and the vegetation of other parts still advancing, shews 

 what they are, notwithstanding their obscuration by the zoophyte. 



A specimen of fine yellow colour, approaching a triangular form, had 

 grown from its original foundation on a leaf of one of the Alga 1 , to the ex- 

 tent of an inch and a quarter in length, by an inch in extreme breadth. 



The systems of both this and of other species consisted of from four 

 to eleven ascidia?, ranged around a common centre. Here the larger ori- 

 fice was distinct, the smaller much less so ; a red speck was interposed be- 

 tween them. From the resemblance of the individual ascidia? composing 

 this product to a plum, if not previously named, it might receive an appel- 

 lative significant of the similitude.— Plate XL. fig. 1.; system, fig. 2., the 

 same enlarged, fig. 3. 



(2.) Another fine specimen invested an Ascidia rustica, which had 

 adhered originally to one of the Algae, and although the orifices of that 

 ascidia yet remained free, the Botryllus was rapidly overspreading it. The 

 whole product would have occupied three-fourths of an irregular hollow 

 sphere fifteen lines in diameter. This Botryllus was entirely covered by 



