200 ANNALS NEW YORK ACADEMY OF SCIENCES 



Diajshragms are of the typical perforated sort and are abundant. The 

 cell walls are thickened and strongl_y moniliform in the mature region. - 



This type probably begins as a basal expansion of considerable extent 

 and thickness, covered underneath by a wrinkled epitheca, and from this 

 expansion the fronds or flattened branches spring. Organisms having 

 such an expanded growth, but otherwise having all the characteristics 

 of the bifoliate fronds, occur associated with them. Amphiporella differs 

 from all the members of the Batostomellidas in its mode of growth, but 

 seems to be especially related to Stenopora. This is shown by the annu- 

 lar thickenings of the walls. It differs in the abundant development of 

 mesopores, the grouping of which is also a peculiar character. 



Type. — Amphiporella maculosa. 



Amphiporella maculosa sp. nov. 



Zoarium large, consisting of a basal expansion, sending off extensive tor- 

 tuous bifoliate fronds. The latter seem seldom to exceed 7 mm. in transverse 

 diameter, but may be 80 mm. or perhaps very much more in length. The cell 

 walls are tbin in the immature region, whieb occupies from one fourth to 

 one third the thickness of the frond. In the mature region, the cells are 

 nearly straight and perpendicular to tbe outer surfaces. Their walls are 

 thick, showing, however, great variability. That is, in tangential sections 

 parallel to the surface, some of tbe walls are rather thin and others are nuicn 

 thickened. Of course, where the walls are thick, the cells are subcircubir and 

 where thinner, proportionately angular. Mesopores are rather abundant, and 

 their distribution is irregular. Occasionally 6 or S or more occur together, 

 making a noticeable macula, but usually they are distributed in twos or threes, 

 though considerable areas can be observed in which none are developed at all. 

 The zocecia vary considerably in size, the larger ones usually occurring where 

 the mesopores are most abundant. The maculte caused by the groups of 

 mesopores are. however, a much more striking feature than the congeries of 

 cells of larger size. Usually G or 7 zocecia occur in a distance of 2 mm. ; 

 when unusually large. .5; or when unusually small. 8. the measurements 

 being made where mesopores do not interfere. 



The walls are generally divided by a distinct median line of darker color 

 than the rest, and in one or two cases where tbe walls are especially thick, 

 the slender, solid line appears broken up into a broader band of granules. 

 Acanthopores are numerous and very large. They usually occur at the angles, 

 but occasionally on the sides of the cells, and not all the angles are occupiea. 

 Where the walls are thick, the acanthopores do not greatly indent the cells, 

 but where the walls are thin, they do indent them, especially when of large 

 size. When the cells are cut longitudinally, the walls have the characteristic 

 swellings conspicuously developed. They are large, abrupt and closely, though 

 somewhat irregularly, arranged. In this view, also, the walls somethnes show 

 fine, transverse bands of lighter and darker color, as if they were originally 

 composed of alternating layers of varying density. The mesopores appear 

 not to be tabulated, except perhaps very rarely. In the zooecial tubes, the 



