634 



MK. e. a. walfoed on some 



close to, though within, the orifice. In an able critique by Mr. E. 

 D. Longe *, examples of Jurassic Diastoporce are shown with the 

 closures in a terminal position, and hence the author infers that 

 there is no substantial difference between them and the opercula of 

 the Chilostomata. 



Prof. D. Brauns f boldly advocates the establishment of an 

 operculate division in the order Cyclostomata, and places under that 

 head the genus Elect, with hlea foliacea as his type. 



Mr. Waters +, working upon Recent and Tertiary material, points 

 out that " The most usual position for the calcareous plate which 

 closes the tube would seem to be about the point where the zocecial 

 tube rises free from the zoarium.'' In the genera Homera, Entalo- 

 phora, and Reticulipora, figured by him, the closures are shown to 

 be so far within the tube as to almost negative the question of their 

 identity with movable opercula. A section of Neuropora damicornis 

 (Lamx.) in my collection shows each zocecial tube with numerous 

 closures or septa, none of which, however, are near the mouth. 



The zocecial surface is not only transversely wrinkled, but also 

 shows some traces of what may possibly be spines. This feature is, 

 however, very obscure, for the surface of well-preserved specimens 

 is often covered with a close and exceedingly delicate calcareous 

 network (fig. 6), partly hiding even the dark lines of the zocecial 

 walls. A similar network of fine threads occurs upon small shells 

 found in the same beds. 



The ocecia are rare and consist of irregular inflations of one or 

 two cells (fig. 4). In one instance the ooecium, apparently an 

 enlarged simple cell, is provided with a smaller opening in addition 

 to the ordinarily large mouth. Other forms of ocecia are external 

 semiglobose chambers enveloping the free parts of one or two cells 

 (fig. 9). The study of this species brings home the fact, so 

 frequently acknowledged by specialists, of the unsatisfactory nature 

 of the classification of the Cyclostomatous Polyzoa; and one cannot 

 put aside the thought that had a few fragments only of it been 

 found, one portion might have done duty as a foliaceous Diastopora, 

 another as an jEntalophora, whilst a third would possibly have been 

 referred to Tubulipora. Notwithstanding some superficial resem- 

 blance to Biastopora cervicomis and D. Lamourouoci, M.-Edw., the 

 exceptional length of the zocecia and their partial freedom sufficiently 

 remove the King's-Sutton species from the Biastoporaz, irrespective 

 of its Tubulipora-like habit of growth. To the Bpiroporce, the 

 foliaceous and adherent forms present an insuperable barrier 

 (though it must not be overlooked that Cricopora abbreviata, Mich., 

 is figured with a flattened base from which the branches spring). 

 The cell- closures do not, as yet, seem to have been discovered either 



* Longe, F. D., " On the Relation of the Escharoid Forms of Oolitic 

 Polyzoa," &c, Geol. Mag. dec. ii. vol. viii. p. 23. 



t " Die Bryozoen des mittleren Jura der Gegend von Metz," \on D. Brauns, in 

 Halle. Zeitsckr. d. deutschen geolog. Gesellschaft, Jahrg. 1879. 



\ Waters, A. W., " Closure of the Cyclostomatous Bryozoa," Linn. Soc. 

 Journ. vol. xvii. p. 400. 



