REPOET ON THE POLTZOA, 11 



Habitat. — Station 172, oflF Tongatabu, 18 fathoms, coral mud. Off Honolulu, 20 to 

 40 fathoms. 



[Australian Seas uhique, New Zealand, &c.] 



This species appears to occur under two rather distinct forms. In one (the typical) 

 it constitutes a beautiful circular expansion, about one inch or more in diameter, 

 composed of short bifurcating branches radiating from a central short stem {vide Brit. 

 Mus. Cat., pt. iii. pi. vii. fig. la), or a more straggling growth in which the branches, 

 though still springing from a more or less excentric point, are much longer, forming 

 elongated forks (loc. cit, fig. ih), constituting a variety to which the term striata might 

 be applied. Very fine specimens of this form occur in the Challenger collection, from 

 Honolulu, whilst a beautiful specimen of the radiate type was procured at Station 172, 

 off Nukalofa, Tongatabu. 



In all the Challenger specimens there is rarely more than one zooecium to represent 

 the lateral series, but in others there are occasionally as many as four {vide Brit. Mus. 

 Cat.,pt. iii. pi. vii. fig. 4), as described by Mr. Macgillivray. The great peculiarity of the 

 species, however, is seen in the coarsely pitted or foveolate surface on th*e sides of the 

 branches, and the series of large pores or pits along the dorsal sulci ; the ooecial chambers 

 also have peculiar sculpture. 



(3) Idmonea marionensis, Busk. 



Idmonea marionensis, Busk, Brit. Mus. Cat., pt. iii. p. 13, pi. xiii. figs. 3, 5 ; pL vii. figs. 7, 8 

 (young state); Waters, Haswell. 

 ICrisina hochstetteriana, Stoliczka, "Novara" Exp. Geol., Theil, Bd. i. p. 113, Taf. xviii. fig. 3; 

 Smitt, i'lorid. Bryoz., p. 6, pi. ii. figs. 11-13. 



^ Character. — Zoarium slender, elongate, very sparingly branched ; stem and branches 

 cylindrical or subcybndrical. Zooecia two to four in each series (most usually two) 

 about 0"15 to 0"20 mm., series wide apart, 07 to 0"8 mm., when entire the innermost the 

 longest. Surface finely but sparsely punctured ; dorsal surface convex, with a fine 

 longitudinal striation. 



Habitat. — Off Marion Islands, 50 to 75 fathoms ; off Prince Edward Islands, 80 to 

 150 fathoms. Station 147, lat. 46° 16' S., long. 48° 27' E., 1600 fathoms. Diatom ooze. 

 Station 151, off Heard Island, 75 fathoms, volcanic mud. Station 320, lat. 37° 17' S., 

 long. 53° 52' W., 600 fathoms, green sand. 



[? Auckland, New Zealand, fossil, Stoliczka; Bay of Naples and Marion Islands, Waters ; 

 Queensland, Haswell.] 



As I have remarked in Brit. Mus. Cat., this species seems to mark a transition between 

 Pustidopora and Idmonea. The cells, however, are always disposed in rows or series on 

 each side of the anterior aspect of the branch, and are for the most part deeply immersed ; 



