476 MR. G. E. VINE OX THE POLYZOA OF 



24. DiAST »poEA FCECUNDA, Yinc. 



1885. I){astoj)ora fcecunda, Tine, Proc. Yorl<s. Geol. rolytccli. 

 Soc. vol. ix. p. y. 



1S89. Diastopora fcecunda, ibid. vol. xi. p. 266. 



In the last of these two papers I have given a bibliography of 

 species allied to the above ; and at one time I was inclined to place 

 the present species under d'Orbigny's name Reptomultisjiarsa glo- 

 merata, Terr. Grot. v. p. 877 ; but, as Ileuss includes this form 

 in his list of synonyms of Berenicea conjluens (Komer), I cannot 

 identify this with any of the forms indicated by him, Tertiary or 

 Cretaceous. 



The lied- Chalk form is rather larger than the one previously 

 described from the Cambridge Greensand ; but its general charac- 

 teristics are similar. Zoarium discoid, and more or less proliferous 

 in habit. The present form is rare in the lied Cnalk and very 

 badly preserved. 



Habitat. In a water-worn piece of Red Chalk. Fossil Xo. 24. 



Horizon. Cambridge Greensand ( — Phosphate-beds); Eed Chalk, 

 Hunstanton. 



2d. Diastopoea eegularis, d'Orb. 



1850. Diastopora regularise d'Orb. Terr. Cret. v. ])\. 636. fig. 10 

 (only). 



1851, Diastopora densata, d'Orb. ibid. pi. 637. figs. 1, 2. 



1851. Diastopora orhicula, d'Orb. ibid. pi. 637. figs. 3, 4. 



1852. Beremcea r^r/uZ«r?>, d'Orb. ibid. p. ,865, pi. i5'6Q. figs. 9, 10; 

 pi. 637. figs. 3, 4. 



The species included in the synonymy by d'Orbigny. as above, 

 dift'er materially in their mode of growth. The D. regidaris, 

 pi. 636. fig. 1 0, has the flabellate character of a Fj-oboscina^ 

 rather than that of a Diastopora^ the discoid form of the species 

 not having been reached ; but in D. densata, pi. 637. fig. 2, w^e 

 have a completed discoid form with the originating cells slightly 

 excentric. D. orbicula, pi. 637. f. 4, has an entirely difterent 

 form of cell and cell-arrangements. The lled-Chalk form is more 

 like D. re,mlaris (pi. 636. fig. 10), and I restrict my identifi- 

 cation to this figure only. The zoarium, though in an advanced 

 Proboscinal stage only, is a true Diastopora ; but it is not wholly 

 discoid. The zomia originate from a primary '^ egg-cell " at the 

 base of the zt)arium, which, unlike that of d'Orbiguy's species, is 

 soon enclosed by the early zooecial growth, after which the growth 

 is upwards and outward, to the right and left, until a disc-like form 

 is reached. The orifices of the originating zooecia, which arc sliort 

 and stunted, are circular; but on two of them these are covered by 

 perforated opercula (" closures "), and some of the cells in other 

 parts of the zoarium bear " closures " as well. The zooecia are 

 broad towai-ds the orifices, narrow towards the base, contiguous, 

 depressed for nearly the whole length ; surface faintly punctate. 



Habitat. On Terebratala hipJicata, Fossil No. 28 a. 



