General History of the Marine Polyzoa. 181 



Ibid. (p. 110 Sep.). 

 Mucronella bicuspis, sp. n. 



This species is ranked by Waters as a variety of his 

 Sniittia tiincisa *. I have not liad the opportunity of 

 examining specimens of the fossil form, which was procured 

 from 'J'ertiary deposits in South Australia and New Zealand ; 

 but, judging from the figure, I can hardly think that there is 

 sufficient ground for identifying it with M. bicusjns. The 

 general character of tlie orifice seems to me to be very different 

 in the two ; the lateral avicularia, a very constant feature of 

 the recent species, are wanting in the fossil, while the tubular 

 avicularia which are so conspicuous a characteristic in the 

 fossil are wanting in ^L hicuspis. The oral denticle of the 

 latter is ])cculiar; but ]Mr. Waters has noticed some variability 

 in this ])ortion of the structure. 



The difierence between the characters of the cell-wall in the 

 two forms is remarkable. Not only are there more of the 

 large pores in S. hiincisa^ but they differ in shape and 

 arrangement from those of the recent species. They form a 

 reticulate covering over the whole surface of the cell, whilst 

 in .1/. hicuspis tiiey are disposed in a single line running 

 across the front of the cell. At the same time it must be 

 admitted that tlie superficial character of the cell-wall is liable 

 to much variation. Mr. Waters's experience as a student of 

 fossil Polyzoa entitles his judgment to much respect in a case 

 of this kind, and on the whole I prefer to leave the question 

 an open one. 



' Annals,' May 1884 (p. 358) t- 

 Memhranijyora margineUa, sp. n. 



Two of the four cells figured bear ooecia ; the cells men- 

 tioned in the description as furnished with a large dark- 

 coloured operculum, " occupying nearly half the area." are 

 probably avicularian. 



Ibid. (p. 358). 

 Smittipora ahyssicoluj Smitt. 



The genus Sviittijwra is, in my judgment, a synonym of 

 OnycJioce/hi, Jul lien, the difterences between the two being 

 quite immaterial. 



* Quart. Joum. Geol. Soc, August 1882, p. 272 ; zOid. February 1887, 

 p. .58. 



t From tliis point to the clo^e of the '' Ap])t'uclix " the pii<.nug is that 

 of the ' Annalsi' and not of the separate ci iiiot-. 



