FISTULIPORID^E. 25 
Zoarium of small ramose cylindrical stems dividing irregularly at somewhat variable dis- 
tances and averaging 2 or 3 mm. in diameter. Surface smooth but exhibiting at regular 
intervals small, solid, slightly depressed maculae, around which the zooecia are somewhat 
larger than usual and radially arranged. Zooecia rounded to oval, 6 in 2 mm. measuring 
in the direction of their greater length, 0.20 to 0.25 mm. in diameter. Zocecial margin 
elevated highest posteriorly, where it forms the lunarium, but gradually diminishing toward 
the anterior end. Interzocecial spaces occupied by vesicles which become filled by a dense 
deposit of tissue at the surface. Axial tube narrow, about 0.60 mm. wide at the most 
expanded portion and becoming reduced to 0.10 mm. where least expanded. 
Through the kindness of Professor Whitfield the writer was enabled to examine the 
types of both Trematopora ostiolata and T. coalescens, with the result as indicated in the 
above synonymy. The type of the latter is a broad, frequently dividing branch differing 
otherwise in no respect from typical specimens of the former. In the writer's opinion, 
this species is merely the basal portion of Chilotrypa ostiolata. In this event the specific 
name coalescens should have precedence as its description precedes that of Trematopora 
ostiolata. However, the latter name has become so grafted into the literature that it 
seems unwise to change it for the hitherto practically unknown form, T. coalescens. 
Occurrence. — Very abundant at Lockport and at all the other Rochester shale localities 
in New York and Canada. Also common in the Osgood beds at Osgood, Ind. 
Catalogue numbers, 35492, 44117, 35490, 35491, U. S. National Museum. 
Genus MEEKOPORA Ulrich. 
Zoarium of broad, bifoliate fronds, celluliferous on both faces; zooecia with numerous 
diaphragms, oblique apertures, and not very prominent lunaria. The following species 
is the earliest known of the genus: 
Meekopora foliacea (Hall). 
PI. VIII, figs. 5, (i; PI. IX, figs. 5, 6. 
Ceramopora foliacea Hall, Nat. Hist. New York, Pal. II, 1852, p. 170, pi. 40E, figs. 3a-c. 
Meekopora foliacea Niekles and Bassler, Bull. U. S. Cool. Survey No. 173, 1900, p. 312. 
Zoarium bifoliate, growing into thin, flat expansions sometimes as much as 40 mm. in 
length and breadth; thickness usually 1 mm. Surface smooth but showing conspicuous 
narrow, solid, elongate macula? pointed distally and dividing, each of the divisions point- 
ing and narrowing in the direction of growth. Apertures oblique, subcircular, 0.20 to 0.25 
mm. in longer diameter and 0.15 to 0.20 mm. in shorter, directed toward the growing 
edge of the zoarium and arranged in rather regular, diagonally intersecting rows. Proxi- 
mal part of the zooecium slightly raised, forming the lunarium; interzocecial spaces solid. 
In vertical sections the zooecia are seen to be at first prostrate along the axis separating 
the two layers and then to bend abruptly toward the surface. The interzocecial space is 
here seen to be filled with vesicles which decrease in size and increase in number as the 
surface is approached. At and just below the surface the vesicles are obscured or replaced 
by a dense calcareous tissue which gives the solid aspect of the interzocecial spaces exter- 
nally. 
The bifoliate growth of this form distinguishes it from all associated fistuliporoids, while 
the other bifoliate bryozoa are so different otherwise that specific mention of them is not 
necessary. Other easily recognized characters are the elongate, branched macula?, the 
zooecia with lunaria pointed distally, and the solid interzocecial spaces. M eekopora foli- 
acea is the earliest known species of the genus, and, as would be expected, has not yet 
developed the typical generic characters. 
Whitfield and Hovey a, in their catalogue of types and figured specimens in the Ameri- 
can Museum of Natural History have regarded Hall's type of C eramopora foliacea as iden- 
tical with Lichenalia concentrica. From a personal examination of the types of the two 
a Bull. Am. Mus. Nat. Hist., vol. 11, pt. 2, 1899, pp. 104, 105. 
