192 NATURAL HISTORY OF 



Those readers who desire a fuller description of these 

 animals will find it, so far as the Pennatulida are con- 

 cerned, in the '' Report on the British Pennatulida/* 

 presented to the Birmingham Natural History Society 

 by Prof. A. Milnes Marshall and Mr. W. P. Marshall 

 in 1882. This may be found in the "Midland Natu- 

 ralist '' for that year. 



The distinguishing features of each family may now . 

 be noticed. 



In the AlcyonidcB the zoophyte is incrusting and 

 destitute of any axis. In the (rorgonidce there is an 

 internal horny axis. In the three remaining families 

 there is a distinct rachis or stem, the zoophytes being 

 more or less pen-shaped. The last-mentioned three 

 families are arranged by Herr KoUiker as follows 

 {Challenger Reports, vol. ii., " Pennatulida "} : — 



Pennatulida. 



Sect. I. Pennatulece. Polyps on leaves. 



(a) Leaves well developed. 



Family Pennatulidce, genus Pennatula. 



(b) Leaves small. 



Family Virgularidce, genus Virgularia. 

 Sect. II. Spicatce. Polyps sessile. 



Family Funiculinidoi, genus Fimiculina. 



The family Alcyonidce contains the single genus 

 Alcyonium. In this genus the zoophyte is sponge-like, 

 and contains no horny axis or stem. The polyps are 

 scattered over the surface, and are retractile. When 

 withdrawn the zoophyte presents anything but an in- 

 viting appearance ; being simply a fleshy mass filled 

 with spiculae, and pitted all over with star-shaped 



