General History of the Marine Pohjzoa. 119 



Family Microporidae. 



Steganopoeella, Smitt. 



SteganoporeUa [Vincularia] Neozdanica^ Busk. 

 (PI .V. figs. 9, 9 a, 9 h.) 



I propose to test the method of classification which adopts 

 the habit of growth as the chief basis of families and genera, 

 by a reference to the history of this species. 



It is (in one of its forms) an undoubted member of the 

 genus Vincularia, Defrance ; the zooecia are arranged round an 

 imaginary axis, so as to form erect, subcylindrical, continuous 

 stems ; the front of the cell is surrounded by a raised border 

 (Busk, B. M. Cat. pt. 2, p. 96). The character of the stem — 

 the mode in which the zocecia are aggregated — is the essential 

 feature of the Vincularian family. 



V. Neozelanica occurs in two or three different forms. Miss 

 Jelly has kindly supplied me with a specimen which spreads 

 in a single layer over the surface of a sponge and is simply 

 incrusting. There is no special modification of structure 

 adapting it to its peculiar habitat, such as we find in Mem- 

 hranipora radicifera j but on one of the few cells of which 

 the dorsal surface is exposed there is a large, stout, spinous 

 process, which is possibly an effort towards the development 

 of some additional means of attachment. 



In the erect cylindrical form the stems are attached by 

 means of a number of chitinous tubular fibres, which are 

 given off from the surface of the lower cells (PI. V. fig. 9 h). 



Amongst the specimens which I owe to Miss Jelly are one 

 or two small fragments of a broader and more compressed 

 type, which approach more nearly to the ordinary Escharine 

 habit. If we examine the zooecium, we find that its structure 

 agrees in every essential point with that which we have in 

 Steganojjorella [Membranipora) majnilabris, Busk. There is, 

 indeed, the closest similarity between the two (compare PI. V. 

 figs. 8 & 9). It would be impossible, with any regard to 

 natural affinity, to place these forms in separate genera*. 

 But S. magnilahris is prevailingly an incrusting form ; occa- 

 sionally it assumes an erect, broadly foliaceous habit of growth. 

 No cylindrical variety of it is known. 



Another species which exhibits the same remarkable struc- 

 tural peculiarities as the two just referred to is Steganojjorella 

 Smittii, Hincks (Hist, of Brit. Mar. Pol. vol. i. p. 178). 

 According to Mr. Goldstein, this species, which is known as 



* Smitt has already made a similar remark {' Floridau Brjozoa/ pt. 2, 

 p. 17). 



