12G MONOGRAPH OF THE FOSSIL FOlA'ZOA OF THE 



C. Janewayi, n. s., fig 7. — Colony encrusting in very irregular patches. Composed 

 of oval to hexagonal cellules arranged in pretty regular quincunx. Cellules convex, 

 generally hexagonal, sometimes very much elongated posteriorly, in which case the 

 proximal end terminates in a point, making the cellule pentangular ; separated by a 

 depressed line, caused by the meeting of the convex surfaces. Mouth terminal, sub- 

 quadrangular, bordered by a lip, very slightly elevated and thickened, occasionally 

 with a tubercle on the proximal margin encroaching on the outline of the mouth. 

 Surface closely perforated by large rounded pores. 



Locality and position. — We have seen but one colony of this species; it is encrusting 

 an undescribed species of oyster from the Cretaceous formation, from " seven miles 

 below Yazoo, Miss." It is in the collection of one of the authors,* and was presented 

 to him by Dr. Janeway, U. S. A., formerly of Princeton, N. J., to whom we dedicate 

 the species. 



In some cases, the anterior margin of the mouth is absent. When this occurs, the 

 lateral margins project forwards in twohorndike processes, the surface of the succeed- 

 ing cellule appearing to serve as one of the orifice. This of course must be a fallacious 

 appearance, due to the extreme tenuit}' of the j>roper cell wall on that side. When 

 the tubercle, behind the apertures is abraded, it shows a perforation, but it is alwaj's 

 entire in sheltered situations, thus proving that such a pore is only accidental. 



The cellules are generally about half as wide as long, but in some instances we have 

 observed them, three times as long as wide. The size and shape of the aperture seems 

 to be very constant; we have seen but little variation. 



We are acquainted with no species bearing a close resemblance to this, or with which 

 it could be confounded. 



C. pumila, n. s., fig 8. — Colony encrusting, composed of minute cellules, arranged 

 in regular lines, but rarely in regular quincunx, which latter form, when it occurs, 

 seems rather to be accidental. Cellules oval, convex, separated from each other by 

 depressed lines. Mouth anterior, not always terminal, subquadrate in form ; without 

 any lip or thickening, but merely pierced in the substance of the surface. Ovarian 

 vesicles not unfrequent ; flattened, rounded, sometimes a little wider than the cellules 

 to which they are attached. Abortive cellules common. 



We have observed two colonies of this species, in both cases encrusting Multicrescis 

 parvicella, G. and H. It is remarkable for the small size of the cellules, and the re- 

 latively small aperture. The cellules are always arranged in radiating rows. New 

 rows commence by an abortive cellule, succeeded by one less than the usual size, and 

 that followed by one attaining ordinary dimensions. Sometimes a cellule appears to 

 have been so crowded by adjoining ones that it has not had room to develope itself. 

 They appear, however 1 , to retain pretty nearly the same shape, differing mainly in size. 



* Mr. Gi\bb. 



