APPENDIX. 389 



acute teeth, two lateral, and one rather longer than the 

 others, and slightly recurved, above. Ovicells — ? 



Hab. — Bass Strait, 45 fathoms, dead shells. 



Colour dirty yellowish white ; polypidom branched, from 

 a common stem ; branches irregular, (?) straggling, pinnate 

 and bipinnate, pinnae and pinnules divaricate at right 

 angles, alternate ; rachis flexuose, or with an angle at the 

 origin of each pinna. The cells are placed at mde distances 

 apart; small and adnate very nearly to the top. The 

 mouth circular, with three large teeth, the one above 

 frequently obscured by adventitious substances, very acute, 

 ascending, and a little recurved. — Sertul. Gayi. (Lamou- 

 roux. Exp. p. 12. pi. 6Q. fig. 89 has four teeth.) 



This species occurs also on the south coast of Patagonia, 

 and the Straits of Magellan ; in the latter locality, how- 

 ever, the habit is much more robust. 



3. S. crisioides^ Lamouroux. (Dynamena.) 



Cells adnate, conical, slightly curved, truncate at bottom, 

 narrow at top ; mouth vertical, external. 



Hab. — Off Cumberland Islands, 27 fathoms. 



Very Hke a Thuiaria, but the cells are not immersed, 

 though very closely adnate, and the outer angle of the 

 square base of each cell is in contact with the upper and 

 back part of the one below it, so that a small triangular 

 space or opening is left below each cell. The branches are 

 very regularly alternate ; and the polypidom is of a light 

 brownish colour. 



h. Cells secund. 



4. S. pristis, (B.) 



Idia pristis, Lamouroux. 



Cells tubular, all contiguous or adnate to each other, and 

 to the rachis, upper half cm'ved laterally, lower half 

 closely adnate, almost immersed in the rachis ; mouth look- 

 ing upwards, rounded, expanded, almost infundibidiform, 

 border slightly scalloped towards the rachis, and projecting 

 externally. Ovicell cyathiform, long narrow with cii'ctilar 



