292 PROCEEDINGS OF THE NATIONAL MUSEUM vol. los 



form or oval area on the frout. Busk obscurely describes five con- 

 verging triangular openings mthin the reniform area but does not 

 picture them on the ovicell in his figures 3a and 3b. Nothing com- 

 parable to them is present in S. canui. Moreover, the ovicells of the 

 latter appear to be much larger proportionately than do those of 

 S. smittiana. 



Lastly, slightly salient mural rims occur around the zooecia of 

 S. canui, sometimes even encroaching partly over the ovicell front 

 (pi. 25,E), whUe Busk says that his zooecia are not separated by septal 

 ridges (mural rims) . 



Smittina canui at first glance might be mistaken for dead white 

 colonies of S. ordinata except for the difference in the degree of ovicell 

 perforation. 



Another species showing close relationship to S. canui is the Smit- 

 tina landsborovii pictured in Osburn's monograph (1952, pi. 47, fig. 2). 

 Both have a small oral avicularium, frontal and ovicell perforated, and 

 broad lyrula. Osburn's specimen differs from S. canui in the shape of 

 the secondary orifice, thinness and shortness of peristome, and 

 extension of peristome over the front of the ovicell. 



Smittina excertaviciilata, new species 



Plate 26 



Diagnosis: Zoarium encrusting, rather heavy-bodied. Mural rims i 

 thin, slightly salient. Zooecial front convex, punctiu-ed by numerous, 

 closely set pores. Nonporous peristome flared laterally. Secondary 

 aperture somewhat reniform or shaped like a horse's hoof, with an 

 elevated, bent, spatulate avicularium set into the hUum area. Avicu- 

 larium medimn sized. Primary orifice with low broad lyrula and 

 two inconspicuous cardelles. Ovicell globose, with a porous frontal 

 area and a secondarily encrusted peripheral area. 



This species is named for the projecting nature of its avicularium 

 from the Latin "exccrtus" (projecting, protruding) and "avicula" 

 (diminutive for bu'd). 



Measurements: The minimum to maximum and average measure- 

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



Z-L, 0.818-1.079 (0.947) Pr-Or- W, 0.202 (Only two) 



Z-W, 0.539-0.835 (0.680) Se-Or-L, 0.158-0.259 (0.216) 



Av-L, 0.086-0.115 (0.095) Se-Or-W, 0.212-0.245 (0.217) 



Av-W, 0.058-0.086 (0.070) Ly-L, 0.029-0.033 (0.030) 



M-L, 0.086 (Only one) Ly- W, 0.072-0.102 (0.095) 



M-W, 0.050 (Only one) Ov-L, 0.288-0.403 (0.349) 



Pr-Oi-L, 0.137 (Only two) Ov-W, 0.317-0.374 (0.340) 



Zoarium: The ivory-colored calcareous zoarium grows over other 

 bryozoan species as well as its own kind. 



I 



