MARYLAND GEOI.OGICAL SURVEY 435 



vestiens. Carter's two calcareous species, H. calcarea and H. vicaryi, 

 also differ too obviously in this and in other respects to require com- 

 parison. 



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

 Chesapeake Beach. 



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

 Johns Hopkins University. 



Order HYDROCORALLIN/E Moseley. 



Genus MILLEASTER n. gen. 



Encrustiiig ( ? or subramose) polyparia, composed of one or more 

 layers. Upper surface rough, exhibiting two sets of large, more or less 

 irregularly distributed jjorcs, tlie one ( ? dactylozooids) with elevated 

 margins and stellate orifices, the other ( ? gastrozooids) fewer in number 

 and occupying the depressed spaces between the elevated apertures, being 

 a little larger, irregularly rounded in shape and the centers from which 

 the astrorhizal grooves diverge. A third set of pores, in this case 

 rounded in form and less than half the size of the other sets, occurs scat- 

 tered among the granules of the interspaces. No columella nor tabulge 

 observed. Septa of the elevated pores strong, not very regular, usually 

 six in number, but varying from four to seven; sometimes joining later- 

 ally so as to leave but a minute central opening. Ccenenchyma cancel- 

 late, granulose at the surface. Skeleton calcareous, apparently com- 

 posed of a loose network of fibers. Astrorhizal grooves always present, 

 but conspicuous only on such portions of the surface where the zooidal 

 pores are either wanting or more widely separated than usual. 



This genus has much in common with Hydractinia, but differs radi- 

 cally in the character of its zooidal pores and really looks very different 

 under a glass. The pseudo-septate pores are much more like those of 

 the Stylasterid^, but are without the columella characterizing mem- 

 bers of that family. From the latter Milleaster is further distinguished 

 by having two distinct sets of large pores and a third smaller set, besides 

 astrorhiza. Excepting the well-developed pseudo-septa of the elevated 

 zooidal pores, Milleaster compares probably best with MiUepora, and it is 

 between this genus and the Stylasterid^ that I believe the affinities of 



