COMPOUND ASCIDIA. 1(17 



indefinite systems, but so closely huddled together, that their form and ar- 

 rangement could be scarcely, if at all, recognised. Many of the ascidia' 

 projected as cones, each with an orifice of four concave circular arcs. 



The specimen was very beautiful ; its colour between buff-orange and 

 Dutch-orange ; and the surface seemed to be granulated with white specks. 

 It decayed in four days. — Plate XL. fig. 6. 



(3.) The tendency to decay is a great embarrassment to continued 

 observation. As substances which are still affixed or rooted so as to be 

 incapable of spontaneous action, become very liable to mould, nature ap- 

 pears to have allotted them such a position that they may be freely 

 washed by the tide. 



Besides other inconveniences, the observer is perplexed by appear- 

 ances, for which he is alike unable to account at the time and to remove, 

 if disturbing his inspection of the object. On one occasion two specimens 

 became so completely studded by yellow dots, as to obscure the arrange- 

 ment of the systems. 



Sometimes the subject decays with the lapse of a single day. A fine 

 yellow Botryllus, with dark orange systems, was decaying in thirty or forty 

 hours.— Plate XLI. fig. 1. 



(4.) It is fortunate, that notwithstanding frequent imperfections and 

 accidents, enough remains to promote our acquaintance with at least the 

 external appearance of this product. 



A beautiful specimen, Plate XLI. fig. 2, much resembling a fig, pen- 

 dent from the substances to which it was attached, extended two inches 

 and a half in length, by an inch in extreme breadth, and was towards three 

 quarters of an inch thick ; the whole surface of pale umber colour, and 

 rather opaque. 



The systems, like so many stars, were composed of from four or five 

 up to eleven ascidia!, environing a large oblong common orifice, which ex- 

 posed some other circular orifices obscurely seen within it at the bottom. 

 — Plate XL. fig. 7. Each ascidia had a swelling shoulder, and the inner 

 side next the central orifice was white, which produced a strong contrast 

 of colour. That the upper orifice was circular, several specimens demon- 

 strated. 



