402 BULLETIN 106, UNITED STATES NATIONAL MUSEUM. 



HIPPOZEUGOSELLA SEXORDINATA, new species. 



Plate 53, figs. 7, 8. 



Description. The zoarium is free, cylindrical, or foliaceous, formed of six 

 longitudinal rows of zooecia. The zooecia are distinct, elongated, elliptical or 

 fusiform; the frontal is very convex and formed of a tremocyst with very small 

 pores. The aperture is suborbicular. somewhat imbedded; the peristome is wide, 

 little salient, interrupted by a small distal tongue. The ovicell is globular, salient, 

 hyperstomial, covered with tremopores like the frontal. On the peristome of each 

 side of the aperture there are two small tubular avicularia with a pivot, the beak 

 of which is turned toward the interior of the aperture. 



.. . fZ.s=0.85mm. 



Measurements. Aperture 7 ..... Zooecia i , _ ,, . .. 



1Z<2=0.10 mm. lfe=0.35-0.40mm. 



Affinities. In its exterior aspect, its convex zooecia, and the smallness of its 

 tremopores, this species much resembles Hippozeugosella inftata. It differs from it 

 in the somewhat larger zooecial dimensions, and especially in the disposition of its 

 zoarium, parts of which are occupied by two supplementary rows of zooecia. 



It therefore approaches close to Eippodiplosella vespertilio, but it differs in 

 its mode of bifurcation, which is identical with that of the other species of the 

 same genus. It may be verified by the examination of the interior of the zooecia. 

 Moreover, its ovicell is closed by a special membrane and not by the operculum. 



Occurrence. Upper Jacksonian (Ocala limestone) : Alachua, Florida. 



Cotypes.C&t. No. 64100, U.S.N.M. 



Genus HIPPADENELLA Canu and Sassier, 1917. 



This new genus is based upon Porella (Flustra) margaritifera Quoy and 

 Gaymard, 1883, and is described on page 497 under the Smittinidae. We believe 

 the genus to be more naturally placed under the Hippoporae, and for that reason 

 have mentioned it at this point. 



Group 3, PEB.ISTOMELLAE Canu and Bassler, 1917. 



Anatomical bibliography. 1ST7. BARROIS, Recherches sur 1'embryologie ries Bryozoaires, pi. 8, 

 figs. 22, 31, 40. 1885. WATEBS, On the use of the avicularian mandible in the determination 

 of the Cheilostomatous Bryozoa, Journal of the Royal Microscopical Society, ser. 3, vol. 5, 

 pi. 14, fig. 25. 1888. JITLLIEN, Mission scientifique du Cap Horn, pi 9, fig. 2. 1909. LEVINSEN, 

 Morphological and systematic studies on the Cheilostomatous Bryozoa, p. 317, pi. 17. 



The aperture is oblique without lyrula, cardelles, or rimule. The ovicell is 

 hyperstomial and embedded in the distal zooecia. It opens above (and nearly 

 opposite) the oblique aperture and below the frontal mucro in a locella, where the 

 operculum operates. 



The disposition of the ovicell in respect to the operculum is close to that of 

 the Smittinidae. Nevertheless the family differs from the Smittinidae in the 

 absence of a peristomie. Between the aperture and the orifice of the ovicell there 

 is, as it were, a sort of chamber or locella in which the operculum moves and takes 



