472 Rev. T. Hincks's Contributions tovmrds a 



Hiantopora ferox is the product of such a process * ; 

 and though in the course of its development it has emerged 

 from the Membraniporine ranks and taken a higher morpho- 

 logical place, he proposes to leave it at the point from 

 which it started, and to unite under one specific name forms 

 which in fact are widely separated by essential differences. 

 . It must be borne in mind that we cannot say with absolute 

 certainty \\\^i H. ferox has been developed from the particular 

 species Memhranipora radicifera and in the special way indi- 

 cated ; this is merely conjectural. But if we could, the evolu- 

 tion has resulted in a distinctive and higher grade of organi- 

 zation, a new type of structure, which it is the function ot a 

 rational classification to recognize and to mark. 



The differences between Uiantopora and Memhranipora 

 are striking and significant. The membranous front wall of 

 the latter, wholly unprotected, or in some cases partially 

 protected by a thin lamina, in others by marginal spines, is 

 arched over in the former by a strong calcareous covering, 

 allowing of various important structural modifications and 

 affecting materially the conditions of life. Granting that the 

 evolution of Hiantopora has proceeded as Mr. Kirkpatrick 

 supposes, it is now far from being a mere " variety " of Mein- 

 hranipora radicifera; it is this phis the morphological 

 changes which have been gradually effected according to 

 evolutional laws. It has lost the characteristic features of 

 the Membraniporine structure, and in any system which 

 aims at exhibiting the natural scheme of life-development it 

 must be placed apart to represent the morphological advance 

 and stand as au evolutional landmark. 



Ibid. (p. 56 Sep.). 



Crihrilina speci'osa, sp. n. 



Busk identities this species (doubtfully) with his C. pJiilo- 

 mela ('Challenger' Report, p. 132, pi. xvii. fig. 6) ; but 

 there can be little doubt that the two forms are distinct. 

 They differ in the shape of the cell and of the orifice, which 

 is suborbicular in C. speciosa. In the latter the costate area 

 does not occupy the whole of the front, as in C. philomela, 

 but is surrounded by a smooth border of cell-wall; the inter- 

 costal furrows are destitute of pores, and the area is traversed 

 by a prominent central keel. There arc also differences be- 

 tween the ooccia of the two forms. 



* "111 the latter (//. fcros) the spines liave undergone further devoloj>- 

 ment ; the horizontal portion on the avieularian side of the eells has 

 grown over the whole area, and fused with the opposite cell-iuarjiu " (he. 

 cit. p. OUi). 



