424 SYSTEMATIC PALEONTOLOGY 



conical or obtuse umbo. Avicularia of two kinds and sizes, both sets 

 very irregularly distributed. Those of the smaller set are ovate and 

 less than half the size of the zooecial orifice, and situated in one of 

 the corners of a zooecium; those of the larger set occupy each the place 

 of a zooecium, have a triangular or acuminate ovate aperture con- 

 siderably larger than the zooecial orifice and have the pointed end or 

 side strongly elevated. Ovicells immersed, somewhat smaller than the 

 zocecia, convex, smooth centrally, punctate marginally, often with an 

 eccentric smooth oval space distinguished from the rest of the surface 

 by an impressed line. 



This very common and characteristic species of the Calvert forma- 

 tion is closely related to L. edax Busk, and like that species had the 

 power of absorbing the shell of certain univalves upon which it grew. 

 Carefully compared L. maculata will be found to differ in having no 

 distinct marginal line separating adjoining zooecia, in having the sur- 

 face of the cells more abundantly punctate and not radially furrowed, 

 in the less acuminate mucro, and the acuminate ovate instead of spatu- 

 late form of the opening of the large avicularia, and in having the 

 pointed end of these strongly elevated. 



Like all the following species referred to LepraUa, we doubt very 

 much that L. edax and L. maculata are strictly congeneric with the 

 species commonly adopted as the type of the genus, but considering the 

 present almost chaotic condition of the classification of the Chilosto- 

 MATA it would be -nothing less than folly to attempt generic revisions 

 in a work like the one in hand. We have therefore contented ourselves 

 with placing our species into the more or less firmly established genera 

 to which they seemed to us to present the greatest affinities, leaving 

 their final disposition for some more pretentious work of the future. 



Occurrence. — Calvert Formation. Plum Point, 3 miles south of 

 Chesapeake Beach. 



Collections. — U. S. National Museum, Maryland Geological Survey. 



Lepralia montifera n. sp. 



Plate CXVI, Fig. 5. 



Description. — Zoarium parasitic, in one or more layers. Zooecia not 

 regularly arranged, subovate, averaging 0.5 mm. or a trifle more in 



