MARYLAND GEOLOGICAL SURVEY 427 



tlie orifice instead of tlie proximal, then this species would be distinct 

 enough to Justify the erection of a new genus for its reception; but 

 until this unusual condition can be demonstrated we think it well to 

 regard it as related to such species as Lepralia pallasiana. We know 

 of none resembling it closely enough to require unusual care in its dis- 

 crimination. 



Occurrence. — St. Mary's FoR^fATiox. Cove Point (on Fecten madi- 

 sonius) . 



Collection. — Maryland Geological Survey. 



Genus PALMICELLARIA Alder. 



Palmicellaria coxvoluta n. sp. 



Plate CXYI, Figs. 2. 3, 4. 



Description. — Zoarium erect, forming loose masses 3 cm. or more in 

 diameter, consisting of broad, bifoliate, convoluted, anastomosing leaves, 

 1.0 mm. or more in thickness. Zoceeia i)rominent, distinct, oval, rhom- 

 boidal or hexagonal, arranged in irregular quincunx, averaging between 

 0.9 mm. and 1.0 mm. in length, and about 0.45 mm. in width; surface 

 rather coarsely punctured ; orifice terminal, the proximal edge overhung 

 by a prominent mucro containing an a\icu]arium the sagittate opening 

 of which is divided into two unequal parts by a septum and lies on the 

 abrupt distal slope of the mucro so as to be nearly or entirely concealed 

 in a front view. When the apex of the mucro is worn or broken away 

 the cavity of the avicularium is exposed to view as a cell immediately 

 behind the orifice and almost equalling it in size. Ovicells small, trans- 

 verse, bulbous, closely united to the cell next above. 



The mucro and avicularium may be absent on many cells of a zoarium, 

 but more of these cells are further peculiar, as shown in fig. 4 on plate 

 CXVI, in having no orifice. The nature of these cells is doubtful. 

 Possibly they are goncecia. 



This seems to be a true Palmicellaria, and of the few species of the 

 genus known P. crihraria (Johnston), which is the only other one de- 

 scribed having the surface of its zooecia punctate, is perhaps the nearest 

 to P. convoluia. Unfortunately, Johnston's species is rare and not well 



