156 Mr. A. W. Waters on the Genus Heteropora. 



i, characteristic form of the interlocking end of the branch, 

 much magnified. (Diagrams.) 



Fig. 50. D. spinispirtdifera, n. sp. Portion of surface viewed from 

 above : a, disks covered with acerate, curved, fusiform, and 

 spinispirulate flesh-spicules ; b, the same without the fiesh- 

 spicules ; c, subsurface spiculation (Sc. A) ; d, four figures 

 showing the gradual transformation of the disk into the sub- 

 surface spiculation c ; e, magnified view of the acerate flesh- 

 spicule ; f, the same of the spinispirula ; g } ultimate form of 

 spicule of the interior ; h, characteristic form of interlocking 

 extremity of branch, much magnified. (Diagrams.) 



Fig. 51. D. kevidiscus, n. sp. Portion of surface viewed from above : 



a, disks covered with the acerate, curved, fusiform flesh-spicule ; 



b, the same without the flesh-spicule (Sc. about D) ; c, upper 

 surface of disk, more magnified, to show its smoothness, faint, 

 concentric, circular lines and depression ; d, under surface of the 

 same, to show spine or shaft ; e, more advanced form of same, 

 showing subdenticulated border ; /, acerate flesh-spicule (Sc. 

 D) ; g, the same, more magnified ; h h, idtimate form of spicule 

 of interior ; i, union of branches by simple apposition. 



XVII. — Note on the Genus Heteropora. 

 By Arthur Wm. Waters, F.G.S. 



I HAVE noticed lately in several reviews an error with regard 

 to Heteropora to which it seems advisable to call attention 

 lest it creep into the literature of the subject. The con- 

 fusion is perhaps the most glaring in a review of Nicholson's 

 'Tabulate Corals,' in 'Nature"' (March 25th)— a review 

 which has a certain family likeness to a notice of the same 

 book which appeared in the l Academy ' some time before, 

 signed by Mr. Moseley, where the same mistake occurs. 



In the notice in ' Nature ' the reviewer says, " Some, as 

 Heteropora, are, according to the late researches of Mr. Busk, 

 of Bryozoan affinity." This shows that the points raised by 

 Mr. Busk have not been appreciated ; for the genus Hetero- 

 pora was created by Blainville for some cretaceous fossil 

 Bryozoa, and the genus, as palaeontologists are well aware, 

 was very abundant in the Jurassic, Cretaceous, and Tertiary 

 periods, occurring frequently in the English Crag ; but no 

 living forms had been described until I drew attention to two 

 living species, from Japan and Australia, in a paper with 

 plate, "On the Occurrence of Recent Heteropora" in the Journ. 

 of the Roy. Micro. Soc.,May 14, 1879, in which I alluded to 

 the minute perforations of the calcareous walls. This is of 

 interest as being a somewhat similar structure to that of some 

 of the so-called tabulate corals, but is not, as some seem to 



