EABLY TERTIARY CHEILOSTOME BRTOZOA. 45 



it is notched below by a rimulo-spiramen designed to conduct the 

 water into the compensatrix. The ovicell is hyperstomial, embedded 

 in the distal zooecia ; it opens above the apertura in the peristomie. 

 No peristome, lyrule, or cardelles. 



This familj'- differs from the Reteporidae in the absence of vibices, 

 vacuoles, and reticulated zoarium, in the cleft on the ovicell, and in 

 the presence of a peristomie. It resembles this family in its em- 

 bedded ovicell and its rimule-spiramen. 



It differs from the Smittinidae in the absence of lyrule, cardelles, 

 median avicularium, and of a peristome with spines. It possesses the 

 same embedded ovicell opening into the peristomie. In the Smittini- 

 dae the peristomie is formed by the development of a peristome with 

 spines; in the Stomachetosellidae it is formed by the thickening of 

 the frontal. 



We have founded our generic classification on the aspect of the 

 ovicell and on the variations of the escape of the larvae, an important 

 function. All the other functions, reproduction, hydrostatic, cal- 

 cification, and passage of the eggs remain exactly the same. 



STOMACHETOSELLA, new genus. 



(Stoma, mouth; ochetos, small canal.) 



The ovicell entirely surrounds the apertura. The frontal is a 

 tremocyst with wide-mouthed tubules. No avicularia. The peri- 

 stomice of the ovicelled zooecia possesses a straighter rimule-spira- 

 men. 



Genotype. — Stomachetosella crassicolUs, new species. Vicksburgian. 



STOMACHETOSELLA CRASSICOLLIS, new species. 



Plate 4, fig. 7. 



Description. — The zoarium is free, bilamellar, formed of broad, 

 undulated branching fronds, more or less fiabelliform. The zocecia 

 are elongated, little distinct; the frontal is convex, smooth, thick, 

 and salient around the apertura, and formed by a tremocyst with 

 large tubules resting on a thin olocyst. The apertura (interior) is 

 orbicular; the peristomice is provided with a triangular rimule- 

 spiramen; the false peristome is thick and smooth. The ovicell is 

 hyperstomial, buried, globular, salient, ornamented with tubular 

 tremopores ; it opens into the peristomie ; it is possibly closed by the 

 operculum ( ? ) ; the rimule-spiramen of the ovicelled zooecia is longer 

 and linear. Laterally, near the apertura there is often a triangular, 

 improminent avicularium, the beak directed above, with pivot. 



