286 PROCEEDINGS OF THE NATIONAL MUSEUM voi,. 105 



Measurements: Minimum to maximum and average measure- 

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



Z-L, 1.238-1.872 (1.594) S^Or-L, 0.202-0.274 (0.246, including 

 Z-W, 0.619-0.864 (0.729) sinus) 



Z-H, 0.533-1.022 (0.749) Se-OR-W, 0.173-0.202 (0.189) 



Av-L, 0.058-0.086 (0.073) Pe-D, 0.259-0.360 (0.317) 



Av-W, 0.043-0.065 (0.055) ZC-H, 0.389-0.619 (0.475) 



B-L, 0.036-0.050 (0.043) ZC-W, 0.490-0.590 (0.539) 



Pr-Or-L, 0.158-0.187 (0.169) Ly-L, 0.022-0.038 (0.025) 



Pr-Or-W, 0.230-0.259 (0.243) Ly-W, 0.036-0.050 (0.044) 

 Se-Or-L, 0.173-0.209 (0.190, excluding FW-T, 0.216-0.3-^6 (0.277) 



sinus) LW-T, 0.043-0.072 (0.061) 



Zoarium: The zoarial surface is a pale buff. The heavy, sturdy 

 zoarium is encrusting, unilaminate, tending sometimes to several 

 layers in thickness when zoids overgrow an older layer. Where a 

 second layer grows over another layer of this species the new layer 

 neglects to put in its own dorsal wall but uses the frontal wall of the 

 underlying layer as a back for its new zoids. No soft polypide parts 

 are in the material. The few pieces found fragment easily. 



Zooecia: The zooecia are large, long and boxlike. A thin, faintly 

 salient rim outlines zooecial boundaries here and there, most frequently 

 around the orifice. Zooecial boundaries are also marked by marginal 

 pores that are slightly larger than the other frontal pores, which are 

 quite uniform in size and distance from each other. 



The frontal is a thick tremocyst, its external surface dusted over 

 with buff. 



The thick lateral and end walls are perforated by pore plates 

 (pi. 23,B). The lateral walls have 6 to 8 of these. Livingstone's 

 specimens had 5 to 7. Some of these pore plates are punctured by 4 

 to 7 smaller pores. The back and front walls are gently convex but 

 the latter sometimes flatten out completely except for the pores and, 

 the raised orifice. The side walls are straight. ,! 



Avicularia: Only one kind of avicularium, the oral, is present. 

 It is visible only in dissected zoids or at the broken ends of the colony 

 as it is small and too deep within the peristomie to be seen from the 

 outside. Moreover, it is located back of the narrow sinus and obliquely 

 oriented. No mandibles are in the present material, but Livingstone 

 describes them as being rounded-triangular. 



Orifice: The orifice is nearly terminal. The frontal of the next 

 distal zoid helps to form its distal wall (pi. 23,C,D). Its sides are 

 in contact with frontal extensions from the neighboring rows of zoids. 

 The orifice is elevated above the rest of the frontal surface. The 

 primarj'^ and secondary orifices look quite different, the secondary 



