

ANTARCTIC BRYOZOA — ROGICK 305 



Smittoidea evelinae (Marcus) 



Plate 32 



Smittina evelinae Marcus, 1937, pp. 109-110, pi. 22, figs. 58a,b. 

 Smittina acaroensis Brown, 1952, pp. 329-331, fig. 253 (not synonymy). 



Diagnosis: Zoarmm chalice or trumpet shaped. Zooecial frontal 

 convex, bordered by one or two rows of areolae and a salient mural 

 rim. A few small pores outline the umbo which bears the sm.all 

 rounded median oral avicularium. Avicularium perpendicular to the 

 zooecia frontal plane, at right angles to the longitudinal axis; semicir- 

 cular mandible directed forward. No avicularia located elsewhere. 

 Two prominent lateral cardelles separated from the low medium-sized 

 lyrula by a broad sinus. Ovicell globose, its frontal surface thin and 

 smooth, perforated by several irregular pores; its peripheral surface 

 granular to pebbly, nonporous, and thicker. 



Measurements: Minimum to maximum and average measure- 

 ments, in millimeters, are given below (for explanation see p. 271). 



Z-L, 0.851-1.332 (1.085) Av-L, 0.072-0.086 (0.082) 



Z-W, 0.518-0.740 (0.644) Av-W, 0.058-0.079 (0.066) 



Ov-L, 0.444-0.555 (0.509) Se-Or-L, 0.173-0.216 (0.180) 



Ov-W, 0.481-0.555 (0.513) Se-Or-W, 0.216-0.281 (0.249) 



Pr-Or-L, 0.173-0.187 (0.183) Op-L, 0.151-0.180 (0.167) 



Pr-Or-W, 0.216-0.266 (0.242) Op-W, 0.187-0.230 (0.213) 



Ly-L, 0.025-0.036 (0.030) M-L, 0.043-0.050 (0.046) 



Ly-W, 0.083-0.101 (0.095) M-W, 0.058-0.072 (0.070) 



Zoarium: The largest colony, from Station 234, measures 56 mm. in 

 height, 40 mm. across its widest part, and 15 mm. in its narrowest 

 diameter. It is ivory colored, rather lightweight, brittle, thin-Avalled, 

 and shaped like a trumpet or chalice. It is unilaminate, with zooecia 

 all facing outward. Its inner (basal) surface is faintly ridged trans- 

 versely and sometimes encrusted with other species. Worm tubes 

 may be present on both frontal and back surfaces. Polypides and 

 embryos occur in many zooecia and ovicells, respectively, 



Zooecia: The large zooecia vary from wedge shaped to hexagonal 

 and are bordered by a thin salient line. Their walls are thin, the thick- 

 est being the gently convex frontal. One or two rows of large, 

 irregular areolar pores border the otherwise externally pebbled or 

 granular frontal. The internal surface of the frontal wall is smooth 

 and punctured by the same pores. A suddenly projecting mucro or 

 umbo supports the oral avicularium of some zooecia but not of others 

 in the same colony. In some zooecia of the same colony the frontal 

 wall curves inward in this area, toward the avicularium (pi. 3 2, A), 

 so that there is no umbo but the avicularium rests on this inwardly 



