314 EEPOET— 1892. 



1852. Genus Semicea, d'Orb., ' Terr. Cret.,' p. 1007. 

 70. Semicea lamellosa, d'Orb., I. c, p. 1008, pi. 787, figs. 17-20. 



1852. Genus Reptomulticava, d'Orb. = Geriopora (pars), Goldf. ; 

 ' Terr. Cret.,' p. 1032. 



80. Reptomnlticava mamillata, d'Orb., Z. c, p. 1040, pi. 794, fig. 1. 



A young example. 



81. Reptomulticava mamilla, d'Orb., I. c, p. 1041, pi. 793, figs. 3, 4. 



Examples of this species are very small. 



1826. Genus Ceeiopoea, Goldf uss, ' Petrifacta.' 



82. Geriopora micropora ? Goldf., ' Petrif .,' p. 33, pi. 10, fig. 4. 



83. „ (Semimulticava) (? tuberculata), d'Orb., pi. 648, fig. 4. 



84. „ sp.(spongites?), Goldf., 'Petrifacta,' p. 35, pi. 10, fig.. 14. 



Sub-order Cheilostomata. 



The classification of Cheilostomatous Polyzoa has uudergone many 

 changes during the last twelve years — or the period embraced since the 

 publication of the first of my various reports on Fossil Polyzoa — and 

 much really good work on the grouping has been done by specialists. It 

 would be impossible in a brief notice like the present one to indicate the 

 full meaning of these changes. By the old investigators zoarial and 

 zooecial characters were studied consecutively, but the diagnosis of a 

 species was moi'e dependent on zoarial than on zooecial characters. In 

 the Cretaceous Polyzoan fauna, as depicted by d'Orbigny in his really 

 great work, we have, we must admit, a peculiar arrangement of group- 

 ing, based on a variety of zoarial growths. Thus, one species having 

 different habits or modes of attachment will have a variety of specific 

 and even generic names. This cumbi'ous method of dealing with the 

 Polyzoan fauna, however, when once mastered, is not such a difficult task 

 as one at first sight would imagine, as the figures of the species help ns 

 to understand auy doubtful reference or diagnosis in the text. It is not, 

 however, the classification of the future ; and, though I have to a large 

 extent followed d'Orbigny in his estimate of species, I have done so after 

 reference to the newer work and suggestions of later authors. Were 

 this a monograph of Cretaceous Polyzoa such a proceeding would be 

 justly regarded as an offence, or at the least as disrespectful to other 

 workers ; but, as this is a report only on British Cretaceous Polyzoa, the 

 course I have adopted may be ungrudgingly allowed, especially as full 

 references are given to the text and atlas of d'Orbigny. 



In my last report ' I quoted from Phillips' ' Manual of Geology ' (1885) 

 Mr. Etheridge's estimate of the Upper- Cretaceous Polyzoan fauna, which 

 he put down at 61 species. In the present report from one horizon of 

 the Upper Chalk alone I have catalogued 125 really good species and 

 varieties ; and in all probability this may be considerably increased when 

 all the Polyzoan fauna is as carefully examined as the Chatham Chalk 

 has been by myself and Mr. Gamble. The general list, however, from all 

 the zones of the Chalk, as given in the zonal divisions at the end of the 

 report, has been nearly trebled. 



• Brit. Assoc. Rep., 1890, p. 378. 



