BRYOZOA 65 



Smittia antarctica sp. nov. 



PI. IV. figs. i,i-/; 



Zoarium bilaminate, calcification fairly solid, irregularlv foliaceous, with spreading 

 calcareous base ; attaining at any rate to some inches in size. 



Zoœcia elongate, hexagonal, with pores on the surface, except the part below the 

 aperture, in which however there is sometimes an elongate avicularium, directed dowmvards, 

 and with a spatulate mandible ; the peristome is much raised and deeph T cleft in the proximal 

 edge, through which a broad lvrula (denticle) can sometimes be distinguished. This denticle, 

 sometimes has a pore, or opening, in the middle, no doubt caused by growth taking place 

 from the two sides. 



The operculum has the lower edge nearly straight, with a muscular ridge placée! 

 diagonally in the upper part, near to the border, and also near each lower corner there is 

 a chitinous thickening. The ridges are more pronounced than is usual in Smittia, and we 

 seem to approach the Ccllaria type of operculum. In the ovicellular zoœcia the peristome 

 projects more forwards, the ovicell is somewhat thrown back, and is perforated with very 

 irregular pores. Some pièces show few, or even no avicularia, whereas in other cases they 

 are nuraerous. 



There are oral glands, and at the tip of each of the 19 tentacles there is an expanded 

 sac, containing, when stained, a dark mass (fig. 1^). In the tip of my Smittia ophidiana 

 (perhaps marmorea Hincks), there are somewhat similar bodies, as also in the tips of the 

 tentacles of Smittia reticulata MacG. from Sydney, and other Smittiœ, but although they 

 hâve been more generally seen in Smittia it is not confined to this genus. In Retepora (see 

 page 80) somewhat the same thing occurs and in Cellepora bispinata Busk, from New South 

 Wales, the tips of the tentacles, in stained préparations are darker, arising partly from 

 abundant nuclei at the tip. However the lumen in S. antarctica widens into a sac, some- 

 times dark balls (stained) being seen in this sac. Hakmer ('), in his paper on the Development 

 of Tubulipora, describes vesicles near the tip of the tentacles of T. plumosa Thomp., but 

 says, that they are not in the lumen of the tentacle. It would seem, that there is abun- 

 dant évidence of an excretory process taking place in the tentacle, and Calvet has described 

 this in more détail in Bugula Sabatieri Calvet ( 2 ). 



There are about ten latéral rosette plates in the entire latéral wall, and two distal 

 plates ; in both cases the plates are near the basai wall. 



This species, in many respects, resembles the Arctic Smittia palmata var. sinuosa Anders- 

 son ( i ), to which I also referred in my paper on the « Bryozoa from Franz Josef Land » (p. 72), 

 as varying in the form of the peristome from Pseudoflustra palmata Sars. The sinuosa is 

 however not strongly calcified, and differs from typical P. palmata very considerably, as 

 there is a distinct oral denticle in sinuosa, whereas none can be discovered in P. palmata ; 



(i| Quart. Joum. Micr, Se, vol. XLI. X. S., p. n5, pi. X, figs. 26, 27. 



(2) Bryozoaires Ectoproctes, p. 72. 



(3) K. A. Andersson, Brvozoen wàhrend der Schwed. Exp. 1S98, 189g, 1900 gesammelt. [Zool. Jahr. 



vol. XV, 1902, p. 546, pi. XXX, fig. 5.) 



IX 



R 21 



