124 



RET. T. HINCKS ON POLTZOA 



111 all the other elements of structure the two forms agree ; 

 and I am inclined to think that T. Smittii (notwithstanding the 

 very distinctive character of the appendage) should rank amongst 

 the varietal forms grouped about the T. Rozieri of Audouin*. 



The calcareous bar across the cavity of the beak immediately 

 below the mandible, which is a very usual element of avicularian 

 structure, is wanting in T. Smittii (as in other cases), and the 

 mandible is simply articulated to a denticular process on each 

 side. The avicularium (which replaces a cell) is developed on a 

 distinct area, extending for some distance below the mandibular 

 portion of the structure. 



Family Myeiozoid^: (part.), Smitt. 

 Schizoporella, Hinchs. 



Schizoporella spongites, Smitt, var. (Plate XII. figs. 7 & 8.) 



Zocecia disposed in lines, moderately convex (sutures shallow), 

 subquadrangular or ovate, destitute of raised boundary-lines; 

 surface reticulate : orifice arched above, the lower margin occu- 

 pied by a rather deep sinus, broad at the opening and tapering 

 off to a rounded point, a small notch at each side, where the 

 sinus commences ; usually a slightly raised border encircling the 

 orifice, which is carried across the front of the cell a little below 

 the sinus ; peristome unarmed : a small avicularium, with pointed 

 mandible directed upwards, placed obliquely close to one side of 

 the orifice, suberect (occasionally one on each side) ; commonly a 

 similar avicularium towards the base of the cell, pointing down- 

 wards. Large spatulate avicularia, replacing a cell, distributed 

 over the zoarium, frequent — the mandible much enlarged to- 

 wards the upper extremity. Ocecia ample, covering entirely the 

 front of the cell above them, and encroaching on those at each 

 side, prominent, rounded, rather broader than high, narrowing 

 towards the front, with a very small orifice; surface reticulate. 



//ab. Forming a sprending crust, white and silvery, on stone. 



[Coast of Florida; Mazatlan.] 



This form, I believe, is rightly referred to Schizoporella spon- 



* "Contributions, kc- TT. Foreign Mcmhraniporwa (continued)," Ann. & 

 Itsg. Nut . Ili-t. &th Her. vol. vi. ]». .'WO, plate xvi. fig. I (JKHO). In this paper I 

 liave described the form in (lira as haying a slender pointed mandible, but this 



description only ftppltai to the more ■olid cent ml portion of it.. 



