Polyzoa^ Ccelenterata^ and Sponges. 453 



somewhat puzzling statement that eight such funnels exist in 

 the specimen figured, the normal number being two or three. 

 These structures probably represent the " diaphragraes trans- 

 verses " of Haime (M^m. Soc. Geol. France, 2" ser. v. p. 210), 

 the " septa " of Busk (Crag Polyzoa, p. 122, pi. xix. fig. 6), 

 Waters (Journ. Roy. Micr. Soc. ii. p. 390) shown to occur 

 in Heteropora, and called " tabulae " by Nicholson (Ann. Nat. 

 Hist. ser. 5, vol. vi. p. 338). The spines of the zooecial tubes 

 of some HeteroporcB and of the cancelli of some Lichenoporcej 

 together with the perforated diaphragms which replace the 

 latter in other species of Lichenopora, are probably all homo- 

 logous with each other and with the present structures in the 

 zooecia of L. verrucaria. I have not seen them elsewhere 

 mentioned as occurring in this genus, and have therefore 

 thought them worthy of a figure. 



Two small specimens have the cancelli and the bases of the 

 zooecial tubes obscured, apparently by an overgrowth of calca- 

 reous matter resembling that described by Hincks {he. cit. 

 p. 479) as an outgrowth of the ooecium. 



Heteropora pelliculata^ Waters? 

 (PL XXI. fig. 3.) 



Heteropora pelliculata, Waters?, Journ. Roy. Micr. Soc. ii. p. 391, pi. xv. 

 figs. 1-4, 7. 



Two very young colonies of what I have little doubt is 

 this species, though their extreme youth renders it almost im- 

 possible to speak with certainty. They consist of dome-shaped, 

 hemispherical incrusting growths, the one 2|,the other 4millim. 

 in diameter, occm'ring on a univalve shell. 



The surface of the colony, at a point halfway between the 

 centre and edge, has polygonal zooecial orifices at regular 

 intervals, each smTOunded by a more or less regular circle of 

 small cancelli, as in fig. 7 J of Waters's plate [loc. cit.) ; at the 

 edge, however, the number of cancelli is much smaller and 

 they are larger than at the centre : they originate just in the 

 same way as the zooecia themselves ; and the outermost ones 

 resemble closely the earliest stage of the zooecia in Lichenopora 

 {Discoporella) . At the actual centre the zooecial orifices 

 themselves are larger than those near the edge ; the cancelli 

 are larger than in the halfway zone. 



The genus is already known from New Zealand, Australia, 

 and the Japanese Seas, and in the fossil state ; its recent distri- 

 bution is now extended to the Arctic regions. Some of Mr. 

 Busk's figures of Heteropora in the ' Crag Polyzoa ' appear to 

 represent young colonies of branching forms ; but the present 



