NORTH AMERICAN EARLY TERTIARY BRYOZOA. 659 



for almost a hundred years it has been recognized by all authors in a zoarial sense. 

 However, the original figures of Proboscina boryi showed the presence of an ovicell 

 formed by an enlargement of the peristomie, a character which we believe of more 

 importance that the form of growth, hitherto depended upon for the recognition 

 of the genus. On the principle of least change we believe it best to retain the 

 name Proboscina for the many multiserial incrusting species in which the ovicell 

 is unknown and to refer the few ovicelled species elsewhere. In this case Probos- 

 cina boryi becomes a member of the new genus Peristomoecia described on page 692. 



The bi- and tri-serial species of Proboscina have a family likeness, which ren- 

 ders them easily discernible. A single ovicell was figured by Waters in 1904 and 

 it is known in another Cretaceous species in the Canu collection. 



The multiserial species of Proboscina are quite variable in their development. 

 Many ovicelled species are known, and, as indicated elsewhere in this work, they 

 belong to different genera and even different families. 



Terminology. This is the same as that of Stomatopora. We add only the 

 maximum width of the zoarium, and sometimes the separation of the tubes. The 

 latter is measured by the distance between two tubes placed at the same height, 

 their peristome being included in the measurement (see text figure 216). 



PROBOSCINA VARIABILIS. new species. 

 Plate 105, figs. 3, 4. 



Description. The zoarium is biserial and incrusts shells. The tubes are oval, 

 smooth, alternately arranged. The peristome is thick, round, salient; the peri- 

 stomie is short, almost perpendicular. 



Maximum width of zoarium ______________ 0.32 mm. 



f * 6 " - 0-0-60 mm. 



Measurements.- 



Diameter or peristome-- ________________ 0.12-0.14 mm. 



Length of peristomie _____________________ 0.16 mm. 



Occurrence. Midwayan: (Claxton limestone). Well at Brundidge, Ala- 

 bama (very rare). 



Holotype.C&t. No. 65250, U.S.N.M. 



PROBOSCINA ADMOTA, new species. 



Plate 105, figs. 7-11. 



Description. The zoarivun is multiserial and incrusts shells or algae; it is 

 formed of thick, claviform fronds, bifurcated and not ramified, more or less sym- 

 metrically arranged on each side of the ancestrula. The tubes are indistinct and 

 arranged in transverse series. The peristomie is thin, salient, orbicular. The peri- 

 stomes are very close to each other. 



f Maximum width of zoarium ___________________ 1.10 mm. 



Measurements.- | Diameter of peristome ________________________ 0.12 mm. 



