GIRTY, NEW CARBONIFEROUS FOSSILS 313 



Callocladia elegans sp. nov. 



Zoarium in the form of hollow tubes which vary in size in different speci- 

 mens, the largest, however, rarely exceeding 5 mm. in diameter. The walls 

 contract and expand more or less irregularly in the same specimen. Inner 

 surface lined with an epitheca. Zoarium thin, 1 mm. more or less in thick- 

 ness, made up of one or more layers each of which is from .43 to .70 mm. in 

 diameter. 



The zooecia are oblique for a short distance, when they bend abruptly to a 

 radial direction, increasing rapidly in size. The walls are thin where oblique 

 and strongly and abruptly thickened where they have a radial direction. The 

 appearance in fact is as if there were two distinct walls, the inner one thin 

 and oblique, to which just back of its extremity is attached another, very 

 much thicker and almost at right angles to it. The projecting end of the 

 inner wall makes a structure like a hemiseptum, and there is evidence of an- 

 other on the opposite side answering to it. On the external surface, the walls 

 have an angular crest from which a slope descends on either hand to the 

 rounded tubes. In thin section, they show a median line which is more or 

 less distinct. The apertures are rather regularly arranged in oblique rows 

 and come about 5 in 2 mm. MaculiB and monticules are absent. Owing to 

 the thick walls, the zooecia are subcircular or obscurely polygonal. The aver- 

 age diameter is .28 mm., but it varies from .21 to .35 mm. Mesopores are 

 abundant, 2 or 3 occurring in the angles where three cells meet. In some 

 cases, a row of mesopores separates a cell from that which lies above or below 

 it on the branch, but laterally the zooecia are in contact. The mesopores are 

 of various shapes and sizes, their naturally angular outline being modified by 

 the thick walls. Acanthopores are fairly abundant o^ the external surface, 

 projecting as small granules from the angles of the cells. In thin section, 

 they are rather obscured in the thick walls, with which they merge to a 

 greater or less degree. Just below the thickened portion, however, they are 

 again conspicuous and indent the cells. The occurrence of projections re- 

 sembling hemisepta seems to be rather regular, one to a zooecium, and they 

 must be interpreted as perforated diaphragms, if this genus is to be admitted 

 to the Batostomellidre. 



Cystodictya pustulosa var. arcta var. nov. 



Zoarium growing in flat bifoliate branches which have a width of about 

 2.5 mm. and a thickness of about .5 mm. There is considerable variation In 

 both these measurements, the width ranging from less than 2.5 mm. to 3 mm. 

 or a little more, and the thickness from somewhat less than .5 mm. to nearly 

 1 mm. The branches, divide frequently but irregularly, bifurcations occurring 

 close together in some examples and far apart in others. My material, though 

 abundant, is too much broken up to show the range of this variation, but 

 6 mm. is perhaps the average length between divisions. The zooecia often 

 appear to have no regular arrangement either longitudinally or diagonally. 

 In some instances they occur in two oblique, intersecting series. Rarely they 

 are developed on short, oblique ridges near the margin of the branch. The 

 longitudinal order is perhaps less conspicuous than the oblique, and it is diffi- 

 cult to determine the number of longitudinal rows in which the zooecia occur. 



