ADDENDA ET CORRIGENDA. 
305 
Aefinitiks. 
This interesting genus has been almost completely overlooked 
in the literature of Bryozoa. It was omitted from the first volume 
of this Catalogue in the hope that further material might be 
available, and would reconcile the apparently conflicting evidence 
of some of the specimens assigned to Chorhtopetalum. The general 
resemblance of the fossil is to the Petaloporidse, but parts of the 
zoarium free of the multilamellar layer suggested that it might 
be one of the Trepostomata. 
A specimen (D. 314:7) had been assigned to Choristopetalum and 
figured on PI. Y. Fig. 10; but from the evidence of that specimen 
alone, the fossil would be regarded as a dendroid Ceriopora. The 
zooecia are not quite uniform in size, but the small ones resemble 
acauthopores rather than mesopores, and are probably only young 
zooecia. The zooecia, therefore, may be regarded as mouomorphic. 
Fortunately, Lonsdale’s type-specimen is available for reference 
in the Museum Collection, and confirms the general accuracy of 
his elaborate series of illustrations. His fig. showing the 
vertical tubes with diaphragms, Avould be consistent with a 
species either of Trepostomata or Cyclostomata. The structures 
illustrated b}^ the other figures (e.g. Ho. 6) show that the affinities 
of the genus are with Sjmrsicavea, from which it is distinguished 
by the multilamellar covering of the axial bundle of zooecia. 
Choristopetalum impar, Lonsdale, 1849. 
Synonymy. 
Heitropora sp., Fitton, 1847. Section from Atherfield to Rockeii End : Quart. 
Journ. Geol. Soc. vol. iii. p. 296. 
Choristopetalum impar ^ Lonsdale, 1849. Notes on Foss. Zooph. : ihid. vol. v. 
pp. 69-77, pi. iv. figs. 5-11. 
,, ,, Edwards & Haime, 1850. Brit. Foss. Corals, p. 70. 
,, ,, Lonsdale, 1851. Memorandum resp. C. impar \ Quart. 
Journ. Geol. Soc. vol. vii. pp. 113-14. 
,, ,, Morris, 1854. Cat. Brit. Foss. 2nd ed., p. 49. 
,, ,, Bristow, 1889. Geol. Isle of Wight, 2nd ed., p. 262. 
,, ,, Newton & Etheridge, 1878. Cat. Cret. Foss. Mus. 
Pract. Geol. pp. 49, 50. 
Diagnosis. 
Zoarium of thick dichotomous branches, varying from 5 to 8 mm. 
in diameter, in branches nearly 40 mm. long. Each branch 
consists of an axial group of longitudinal zooecia, surrounded 
X 
