NORTH AMERICAN EARLY TERTIAKY BRYOZOA. 389 



disposed below the aperture. On the lower face, the zooecia are smooth, convex 

 and ornamented with numerous small hydrostatic prickles. 



,, |A=0.23mm. . [7,3=0.75-0.85 mm. 



Measurements. Aperture \ , . 1tr /ooecia , -_ orv 



Ua=0.17mm. lfe=0.65-O.SOmin. 



Affinities. This is the species which has the most resemblance to the type 

 of the genus Hippomenella mucronclliformis Waters, 1899. from Madeira as much 

 in its frontal as in the form of its aperture. It differs from it in its much larger 

 aperture (7i=0.23 and not 0.16 mm.), in its avicularia of the same size, in the 

 absence of a small oral mucro, and in its hydrostatic prickles. 



It differs clearly from the other species of Hippomenella in the hexagonal form 

 of the zooecia. 



The frontal is formed of a very thin pleurocyst (fig. 4). very distinct from the 

 subjacent olocyst, from which it may be separated. 



Occurrence. Vicksburgian ("Chimney rock" of Marianna limestone) : One 

 mile north of Monroeville, Alabama (very common). 



Cotypes.Q.*.\. No. 64278, U.S.N.M. 



Group 3. ZOARIUM INCRTJSTING. 

 HIPPOMENELLA PUNCTATA, new species. 



Plate 51, figs. 1-3. 



Description. The zoarium incrusts" shells and bryozoa, especially the Celle- 

 pores. The zooecia are distinct, very elongated, fusiform, separated by a furrow; 

 the frontal is convex, smooth in the middle, surrounded by a double row of small 

 areolae and formed of an olocyst surmounted by a distinct pleurocyst. The aper- 

 ture is elliptical, elongated, provided with two small cardelles placed very low; 

 the peristome is thin and garnished with six distal spines. The ovicell is globular, 

 salient, little imbedded in the distal zooecia, never closed by the operculum; the 

 lateral areas almost disappear under a tremocyst, which has numerous small pores 

 in quincunx. The avicularium is small, salient, triangular, placed eccentrically 

 before the aperture ; it is provided with a pivot and its beak is pointed downward. 



f^a 0.18-0.20 mm. . f 3=0.80-0.90 mm. 



Measurements. Aperture , ,,... .,- Zooecia {, _ ,,._ 



Ua=0.140.15 mm. 1/3=0.35-0.45 mm. 



Affinities. It is easy to understand in this species the deposit of the pleuro- 

 cyst, the elements of which begin to be deposited around the areolae. The buds 

 of the internal endocyst of which the areolae are the traces, reunite by coalescence 

 1o form a superior endocyst and continue therefore to be able to secrete and deposit 

 the pleurocyst. 



This species differs from Hippomenella rotula in the presence of its spines, its 

 ovicell with small pores and not with large costules, and its zoarium incrusting and 

 not bilamellar. 



It differs from Hippomenella radicata in its larger dimensions, its ovicell with 

 pores more numerous and smaller, its unique avicularia and its zoarium incrusting 

 and not unilamellar. 



