606 BULLETIN 106, UNITED STATES NATIONAL MUSEUM. 



long, surrounded by areolae; the oral mucro bears no avicularia. The deep zooecia 

 are visible only by their apertnra. The incomplete zooecia are rare. 



fAa=0.10-0.12 mm. 

 Measurements. Apertura , -,,, r . nn 



\la 0.10-0.12 mm. 



Variations. This species is well characterized by its large, oral avicularium and 

 by the fissure of its ovicell. The marginal zooecia exist only on the solid substratum 

 (shells or bryozoa) (fig. 4). They evidently do not exist on the hollow tubular 

 zoaria, which surround the radicells of algae. Likewise the incomplete zooecia 

 exist only on the latter (fig. 5). In the interior the operculum articulates on two 

 small condyles. 



Affinities. This species much resembles Holoporella altirostris. It differs from 

 it in its larger apertura and in the absence of pedunculate avicularia on the deep 

 zooecia. 



It differs from Iloloporella albirostris Smitt, 1872, of the waters of Florida, 

 in the, absence of the interzooecial avicularia, but it is very closely related. 



Occurrence. Lower Jacksonian (Moodys marl) : Jackson, Mississippi (com- 

 mon ) . 



Jacksonian (Zeuglodon zone) : Shubuta, Mississippi (rare). 



Vicksburgian (Marianna limestone) : AVest bank of Conecuh River, Escambia 

 County, Alabama (rare) ; Murder Creek, east of Castlebury, Conecuh County, 

 Alabama (rare). 



Cotypes.Czt. Nos. 64216, 64217, U.S.N.M. 



HOLOPORELLA ALTIROSTRIS, new species. 



Plate 7D, figs. 16-20. 



Description. The zoarium forms small globular masses attached to other 

 bryozoa, shells, or algae. The superficial zooecia are very salient, erect, irregular ; 

 the frontal is smooth and terminated by a prominent beak, bearing an enormous 

 oral avicularium with pivot; the terminal portion of the beak is fringed and 

 partially hides the apertura. The apertura is oblique, semilunar and formed of 

 a large, finely crenulated anter, separated by two small cardelles placed very low 

 from a concave poster ; the peristome, thin and little salient, bears two symmetrical 

 spines. The ovicell is recumbent, hyperstomial, transverse, smooth, globular, 

 widely open above the apertura and at the level of the large oral avicularium; 

 it bears in front either a small, fragile, cicatrix or a fissure. The deep zooecia 

 have no frontal; their apertura is visible and the oral avicularium is quite salient 

 and pedunculate. The incomplete zooecia are rare. 



rAa=0.09mm. 

 Measurements. Apertura <, ... ., - 



lZa=0.10mm. 



Affinities. In its zoarium and in its ovicell. sometimes fissured, this species 

 much resembles Holoporella fissurata. It differs from it in its much larger oral 

 avicularium becoming pedunculate on the deep zooecia. 



