Вгз'огоа. 455 



Fam. Smittinidae. 



Smittina arctica Norman. 



Escharella porifera, forma majascala Smilt, op. cit. 1867, Appendix 



p. 9 & 10, pi. 24, figs. 36—38. 

 Smittia arctica Norman, Trondhjem Fiord, Polyzoa, Annals Nat. Hist. 



6 S. Vol. XIII, 1894, p. 128. 

 Smittia Lansborovii, forma porifera Hincks, Annals Nat. Hist. 6 S. 



Vol. 1, 1888, p. 225, PI. XIV, fig. 2. 

 Smittia majascala Nordgaard, Hydrograph, and Biologicai Invest, in 



Norwegian Fiords, 1905, p. 170, PI. IV, figs. 36—38. 

 Smittia porifera Osburn, op. cit. p. 245, PI. XXVI, fig. 64. 



Smittia arctica Nordgaard, Bryozoa from the 2nd Fram Exp. 



1898—1902 1906, p. 29. 

 (PI. XXII, figs. 1, 2, 3). 



The zooecia have their whole frontal surface provided with nu- 

 merous pores, among which is found a large number of small, sharply 

 defined tubercles. The aperture is nearly circular, but provided 

 with a broad proximal sinus divided into two smaller ones by a 

 median tooth, more or less developed, mostly slender as a rule de- 

 creasing in breadth towards the truncated end. In rare cases it 

 attains a larger breadth and may sometimes be bicuspidate. The 

 sinus is bordered by two distinctly projecting lateral teeth, the tips 

 of which are as a rule obtusely rounded. The peristome is faintly 

 developed, and besides a more or less projecting very tuberculous 

 distal lip there may be found a small lateral projection which is 

 most developed in the ooeciferous ooecia. The operculum, which 

 is faintly chitinized, is provided on each side with a chitinous ridge, 

 the distal end of w^hicli serves as a point of attachment for the oper- 

 cular muscle, while the proximal end is in connection with the cor- 

 responding lateral tooth. The convex, mostly saddle-shaped distal 

 wall is provided on each side near to the lateral wall with 3 — 4 

 single-pored rosette-plates, and the distal half of each lateral wall 

 with 2 — 3 ovate or elongate rosette-plates w^th 2—6 pores. A small 

 number of these may sometimes be replaced by pore-chambers. 



The very projecting sub-oral avicularium, which never conceals 

 the median tooth has a rounded mandible which is a little longer 

 than broad (fig. 2), and the mandibular area is at least twice as high 

 as the sub-mandibular one. 



The ooecia, which are sometimes as high as broad, very seldom 

 take up the whole breadth of the distal zooecium. They are very 

 convex, tuberculous, and provided with a mor eor less well-developed 

 shade-formed projection, but only in very few zooecia have I seen 



