GIBTY, NEW CARBONIFEROUS FOSSILS 193 



Dyscritella subgen. nov. 



The two species included in this group are ramose with well-differenti- 

 ated and rather thick, mature zones. Zocecia, mesopores and acantho- 

 pores are all present. Tlie zooecia are rounded in section, circular or oval. 

 Mesopores are fairly numerous, rather more numerous than in typical 

 BatostomeUa and much less numerous than in typical Lioclema. The 

 acanthopores are also fairly numerous and in both species of two differ- 

 ent sizes. In typical BatostomeUa, the acanthopores are much more 

 numerous and all small. In tj-pical Lioclema, the acanthopores are per- 

 liaps not quite so numerous and all large. Tabula appear to be entirely 

 lacking in both mesopores and zocecia. In typical Lioclema, tabulae are 

 alnindant in the mesopores and rather rare in the zooecia. In Batosto- 

 meUa, the diaphragms are remote, delicate and originally perforated. The 

 mesopores are open as in BatostomeUa, not closed as in the typical sec- 

 tion of Lioclema. 



On the whole, perhaps, these species are more closely allied to Batosto- 

 meUa than to Lioclema, but they can hardly be included under either 

 genus without introducing anomalous features. 



Type. — Dyscritella rohusta. 



Dyscritella robusta sp. nov. 



Zoarium consisting of solid cylindrical stems having a diameter of about 

 S mm. The stems increase, according to the only specimen examined, by 

 lateral branching, the branches making an angle of about 45° with the main 

 stem. Zocecia are longitudinal in the axial region, those nearer the side lean- 

 ing slightly outward. By a rather abrupt turn, they assume a radial direc- 

 tion, and at the same time their walls are thicljened, and mesopores and acan- 

 thopores are introduced. The mature zone occupies one fourth of the width 

 at either end of the axis. 



The apertures are small, circular to oval, from .083 to .11 mm. in diameter. 

 Mesopores are fairly numerous, varying in number and circular in shape. 

 Rather extensive aggregations of these cells make large maculie, but for the 

 most part, they occur in single rows between the zooecia, or in groups of two 

 or more in the angles between several of the tubes. Occasionally the zocecia 

 are in juxtaposition without any mesopores intervening. As many as 10 or 11 

 of the zooecia occur in 2 mm. (though straight rows of that length are hard 

 to find), where the mesopores are in normal abunadnce. In or near a macula, 

 the number is of course much less. The walls are thick, varying from one 

 half the diameter of a zooecium to twice the diameter. Acanthopores are 

 abundant and of two orders, differing greatly in size. The larger ones are 

 extremely large and rather scantily developed, two to four near each zooecium. 

 The smaller acanthopores are very unequally distributed, being rare in some 

 areas and abundant in others. Tabulje seem to be entirely absent from both 

 mesopores and zooecia. The mesopores. however, are hardly discriminable in 

 longitudinal or transverse sections, and may be tabulated. 



