NORTH AMERICAN KARLV TERTIARY BRYOZOA. 539 



aperture is buried at the bottom of a peristomie; it is irregular and formed by 

 the development of two lateral lips, separated by a pseudotinuile. No avicularia. 



,, rr (3=0.50 mm. 



Measurements. Zooecia , 



I? 2=0.25 mm. 



Affinities. Only the figured specimen has been found; it bears no ovicell. It 

 differs from the type of the genus in its smooth and nonporous frontal and in its 

 zoarium, which is free and does not incrust algae. 



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



Ilolotype.C&t. No. 64181, U.S.N.M. 



Family TUBUCELLARIIDAE Busk, 1884. 



/libUograplii/ (Anatomical). 1907. WATERS, Tubucellsiria : its Species and Ovicells, Journal 

 Linneaii Society, London, Zoology, vol. 30. p. 126, pis. 15, 16. 1909. LF.VINSKN, Morphological 

 and systematic studies on the Cheilostomatous Bryozon, p. 304, pi. 16, figs. 3, 4, 5. 



The zooecia have no spines ; their frontal is formed of long tremocystal tubules 

 surmounting a thin perforated olocyst. The septulae are numerous, scattered, 

 and mnltiporous. The ovicell is vestibular, being formed by a great expansion of 

 the peristomie, which is always very long. The frontal bears an ascopore opening 

 into the compensation sac. 



Terminology. The very considerable thickening of the frontal develops a very 

 long peristomie^ the lower orifice of which is closed by the operculum and forms 

 the true apertura; its outer orifice is the peristomiee, which is more irregular in 

 form. The latter is surrounded by a more or less thickened and salient penstome. 

 Exteriorly, the upper part of the zooecia, which corresponds to the peristomie, is the 

 peristomiale. 



Anatomical stnicture. The zooecia are provided with closely placed pits or 

 areas separated by ridges, each surrounding a pore. This disposition is the rule 

 when the tremocyst covers a perforated olocyst. These pits or areas are the ex- 

 tremities of well developed tubules, as in the family Myriozoumidae. 



The ovicelled zooecia have a particular form like the gonoecia of the Adeonidae; 

 but they have not at all the same structure. The larvae develop in a large expan- 

 sion of the peristomie, forming a peristomial ovicell. In its interior, there is at 

 first a normal polypide. This disappears by histolysis and a diminutive and very 

 vigorous polypide succeeds it. in which the circular canal and the ganglion may be 

 observed. This communicates with the opening of the ovicell and is accompanied 

 by a voluminous ovary. 



The diaphragm (irisoid) is attached to the operculum and to the Avail. 



There is a large number of delicate muscles attached to the compansation sac, 

 a'nd the latter communicates with the exterior by the ascopore. 



The zoarium is free, unilamellar, bilamellar. or cylindrical. It is often articu- 

 lated and radicellated. The articulated zoarium generally lives among algae, the 

 mobility and flexibility of which it must share. 



