a General History of the Marine Polyzoa. 83 



appendage identical in structure with that of the genera 

 Bugula and Bicellaria* '. In other respects it exhibits points 

 of affinity with the last named. The zoarium is but slightly 

 calcified ; the zooecia are disposed in lines, and are in some 

 degree suberect and overlap one another above. The avicu- 

 laria are placed in the same position as those of Bugula, which 

 they exactly resemble. Altogether the species has much the 

 general appearance of a decumbent Bugula, whilst at the same 

 time it is technically an undoubted Membranipora. It helps 

 to connect the two types. The spines are massive, subclavate, 

 white and polished, and constitute a striking feature. 



I have much pleasure in dedicating this very interesting 

 form to so able a naturalist as my friend Mr. Carter. 



Membranipora pura, n. sp. (PI. XI. fig. 3.) 



Zooecia large, more or less ovate, closely united, surrounded 

 by a perfectly smooth border, which slopes up to a ridge-like, 

 marginal line • front wall wholly membranous ; at the top of 

 the cell two stout spinous processes, one on each side, which 

 are frequently united by an elevation of the margin (forming 

 a wall between them). Avicularia none. Ooecium(?). Zoa- 

 rium white, smooth, glossy, subhy aline. 



Loc. Australia or New Zealand (Miss Jelly). 



It would be almost impossible to frame a description of this 

 form that would be sufficient in itself to ensure certain 

 identification ; a figure is indispensable. The same may be 

 said of great numbers of species ; in the case of the Polyzoa, 

 at least, the practice cannot be too much reprobated of pub- 

 lishing new names unaccompanied by a recognizable figure of 

 the form intended. 



In M.pura the cells are of large size, sometimes regularly 

 oval, sometimes broad-ovate, arched above and with the lower 

 margin somewhat flattened, sometimes expanded above and 

 narrowing off slightly towards the lower extremity. They are 

 closely soldered together, so that there is only an inconspicu- 

 ous furrow between the contiguous margins ; the border is 

 quite smooth, without any trace of beading or crenature. The 

 screen-like elevation of the peristome between the two spines 

 at the top is a good diagnostic mark, but it is not present on 

 all the zooecia. 



* M. minax, Smitt (M. pri?iceps, mihi), is furnished with an ayicu- 

 larium which has the form of the "bird's head ;" but it is fixed (destitute 

 of a basal joint) and wholly calcareous, instead of being partly corneous 

 and partly calcareous. M." Carter i is the only species in which the per- 

 fect " articulated " appendage has yet been met with. 



G* 



