608 



BULLETIN 106, UNITED STATES NATIONAL MUSEUM. 



is small, elongated, and formed of a large circular anter separated by two small 

 triangular cardelles from an almost straight poster; the peristome is very thick, 

 salient; it bounds an infimclibuliform peristomie and bears eight spines. The ovi- 

 cell is hyperstomial, recumbent, very small, little salient, smooth ; it is widely open 

 in the peristomie. Laterally and near the apertura there is a small, oblique, little 

 salient avicularium. 



f7iffl=0.15mm. 



Measurements. Apertura , , . 



I la =0.10 mm. 



Occurrence. Middle Jacksonian: Wilmington, North Carolina (rare); Rich 

 Hill, Crawford County, Georgia (rare). 

 Holotype.Cnt. No. 64219, U.S.N.M. 



HOLOPORELLA PISIFORMIS, new species 



Plate 77, figs. 8-11. 



Description. The zoarium is formed of small, globular masses, of the size of 

 a pea. The superficial zooecia are small, raised, and entirely smooth. The apertura 



is semilunar and provided with two large cardelles; 

 the peristomice is very irregular; its proximal edge 

 bears two lips more or less coalescent and sometimes 

 a small oral, elliptical avicularium. The ovicell is 

 hyperstomial, recumbent, globular, smooth, widely 

 open above the apertura. The deep zooecia are visi- 

 ble only by their apertura. 



,, Aa=0.08mm. 



Measurements. Apertura , ...... 



7<z=0.07 mm. 



P-...S 



PIG. 182. Holoporella pisiform/is, 



new species. 



A-C. Sketches showing varia- 

 tions in the form of the peristomice. 

 D. Sketch of apertura. a, mucro; 

 c, cardelles; p, lateral apophysis; 

 psp, pseudospiramen; r, rimule. 



Variations. This small species is remarkable in 

 the disconcerting irregularity of its peristomice 

 hiding the apertura. Certain zooecia have a salient 

 mucro (fig. 11) ; then the two cardelles are replaced 

 by two peristomial apophyses separated from the 

 mucro by two pseudorimules. Other zooecia bear two 

 apophyses separated by a rimule (fig. 9); the latter may be joined (fig. 10), 

 surrounding thus a sort of spiramen. All these details have the most minute 

 dimensions. 



Affinities. This species is well characterized by its small dimensions and its 

 peristomial variations. It differs from Holoporella separata in its smaller zooecia 

 and in the absence of pedunculate avicularia issuing from the deep zooecia. 



It differs from Holoporella mieropora with small zooecial dimensions, in its 

 more elevated zooecia, its smaller zoarium and in its much larger apertura (ha 

 O.OS and not 0.05 mm.). 



Occurrence. Middle Jacksonian: Wilmington, North Carolina (common); 

 Rich Hill, Crawford County, Georgia (rare). 

 Cotypes.C&t. No. 64223. U.S.N.M. 



