



General History of the Marine Polyzoa. 195 



A curious element of structure (not noticed by Busk) is the 

 line of tall spines which fringes each side of the branch ; it 

 may probably act as a protective barrier. In this case all the 

 appendages seem to me to have probably the same general 

 function, and to be charged with the office of defending the 

 polypide in various ways, and securing for it the conditions of 

 healthy life. The opercular shield, the cleansing sweep of the 

 Betas, the flapping of the mandibles, the fence of unyielding 

 spines, all these seem to point in one direction. 



In 8. cervicornis, with its slender habit and delicate colour 

 and texture, with its decorated shield and rich profusion of 

 curious apparatus, we have certainly one of the most beauti- 

 ful and most admirably equipped of its tribe. 



Family Bicellariidae. 

 Stirparia, Goldstein. 



Gen. char. — Zoarium consisting of erect segmented stems, 

 chitinous or calcareous, and of celliferous branches, which 

 originate in more or less flabellate tufts close to the summit of 



the segments. Zocecia of the normal Bicellarian type, turbi- 

 nate, somewhat free above; aperture looking more or less 

 upward, turned obliquely inwards, inferior portion of the cells 

 subtubular. Avicularia articulated. 



I have revised the characters of this genus, which was in- 

 stituted by Goldstein for a remarkable Australian form, that 

 it may include the kindred species which I am about to 

 describe. There are some striking points of difference be- 

 tween the two, but none that would warrant their removal to 

 separate groups. So far as the zooecia are concerned, they are 

 both typical Bicellarice ; the development of erect stems of 

 peculiar structure, on which the celliferous branches are borne, 

 is the one character which differentiates them both from the 

 ordinary members of this genus. In S. annulate. Maple- 

 stone *, the stems are represented as composed of a " soft cor- 

 neous " material, and the segments, though distinctly marked 

 out by rather deep constrictions, are said not to be articulated. 

 They are also very .prettily annulated through a considerable 

 portion of their length. In the form which i have to describe 

 the sterns are calcareous, divided into segments by well- 

 marked corneous joints, and with a smooth surface. The 

 internodes, too, instead of being of uniform length, are alter- 

 nately shorter and longer ; and it would seem that the celli- 



• 



Journ. Microscop. Soc Victoria, 1879. 



