from the Firth of Forth, 81 



about the fourth of a Hne in length, and appear through the mi- 

 croscope as minute curved pins spread irregularly through the 

 whole fleshy substance of the animal : they do not impede the irri- 

 tabihty of that substance, as, on tearing off a portion of it par- 

 tiaQy from the shell, we observe it slowly contract its dimensions, 

 and a portion of it entirely detached, soon becomes contracted 

 and more hard to the feel. 



This zoophyte, though one of the least attractive in its exter- 

 nal appg^arance, and one of the most common inhabitants of our 

 coast, presents to the comparative anatomist a new and very in- 

 teresting combination of properties ; it is closely allied to the AI- 

 cyonmm by its contractile fleshy texture, and by its distinct though 

 microscopic polypi ; and it is allied to the Sponge by its siHceous 

 tubular spicula, ramified internal canals, tubular papillae, regu- 

 lar currents, and the distribution of its ova. It differs, however, 

 from the Alcyonium, in not presenting a free surface, covered 

 with a coriaceous integument, marked with stellate pores for the 

 lodgment of distinct polypi ; and it differs from the Sponge in 

 the obvious contractility of its papillae and general texture, in its 

 possessing distinct polypi, and in its surface not being free, and 

 covered with open angular pores. It constitutes a distinct genus, 

 forming a connecting link between the Alcyonium and the Sponge^ 

 and throws much light on the nature of the latter zoophyte. I 

 have termed this genus Cliona, (from ;cAg«w, claudo), from its 

 most obvious and remarkable property of retracting and shutting 

 the papillae when irritated ; and the above described species, the 

 only one I have met with, is named celata, from its concealed 

 and secure habitation within the substance of oyster-shells. It 

 has an extensive distribution in the Frith of Forth, occurring 

 abundantly in the oyster-beds at Prestonpans, off* Inchkeith, and 

 in the Roads. I have only found it in the shell of the t?ommon 

 oyster, and it may be questioned whether the sharp siliceous spi- 

 cula, and constant currents of its papillae, do not exert some in- 

 fluence in forming or enlarging the habitation of this zoophyte. 



APRIL- — JULY 18S6. Y 



