BRYOZOAN FAUNA OF VIN/CENTOWN LIMESAND 75 



and the ascopore. But the irregularities of gemmation and of cal- 

 cification much derange this fundamental arrangement, and one can 

 see there only a deceptive irregularity, which, however, can be under- 

 stood by close study. 



The peristomice is frequently elliptical and transverse. On the 

 edge of the zoarial branches the ascopores are much larger, and their 

 diameter frequently attains that of the peristomices themselves. 



Affinities. — Of the three species of Beisselina with similar exterior 

 aspect discovered in the Vincentown limesand, this one is the smallest 

 in its micrometric dimensions. It is also the most irregular, and 

 finally it never shows a peristomice entirely surrounded by at least 

 four avicularia. Gabb and Horn's figure does not show salient peri- 

 stomices regularly surrounded by avicularia, so that Ulrich and 

 Bassler's determination of 1907 is exact. 



Occurrence. — Vincentown limesand: Mullica Hill and Timber 

 Creek, N.J. (Gabb and Horn) ; common at Vincentown and near 

 Blackwoodstown, N.J. 



Plesiotypes.— U.S.N.M. No. 73936. 



BEISSELINA INTERMEDIA, new species 



Plate 18, Figures 2, 3 



Description. — The zoarium is free, bijamellar, formed of two 

 lamellae opposed and inseparable; the fronds are wide, thick, ellip- 

 tical in cross section, bifurcated in the same plane. The zooecia are 

 indistinct, elongated, arranged in quincunx; the frontal is buried 

 under the avicularia visible exteriorly; it bears an ascopore at some 

 distance from the peristomice and opening into the interior of the 

 zooecium below the operculum. The aperture is buried at the bot- 

 tom of a long oblique peristomie; the latter is formed by frontal 

 avicularia, which have very thick walls, by a salient peristome, and 

 by the peristomial avicularia ; the peristomice is orbicular with a 

 diameter intermediate between that of B. lonsdalei and B. labiata, 

 surrounded by 4 to 6 small, salient avicularia with or without a 

 pivot and arranged like a crown. Each frontal is covered by 3 to 

 5 small, thick-walled avicularia irregularly arranged, in which the 

 orifice is small and without a pivot. Frequently the small prox- 

 imal avicularium develops so much that it becomes a large 

 avicularium covering all the frontal; it is triangular with pivot; 

 its beak is pointed and salient above the zoarial plane. 



Measurements . — 



rj . fZs=0.75mm. _, . J . (7i.» = 0.125 mm. 

 Zooecia{ . _ _ Peristomice^ , „ .„„ 



|/s = 0.3 mm. yip = 0.125 mm. 



21 or 22 zooecia in 4 sq. mm. 



177635—33 6 



