160 
PALEONTOLOGY OF NEW-YORK. 
554. 2. CLATHROPORA FRONDOSA (n. sp.). 
Pl. XL B. Fig. 5 a-e. 
Frond reticulate, expanded, flabellate, or funnel-shaped ; the two surfaces regularly and 
equally celluliferous ; cells with rhomboidal or oblong quadrangular apertures opening obliquely 
upward ; tubular cells reaching to the centre, and gradually enlarging towards the aperture. 
This species consists of a thin expanded frond, produced by the anastomosing of broad flat¬ 
tened branches. It appears more like a perforated flabellate frond, than a reticulate structure. 
It has the general appearance of Retepora, from which it is not readily distinguished unless 
both sides are examined. The form of the apertures of the cells, however, is more quadrangular 
than in any species of Retepora I have seen, and this character may be of service in de¬ 
ciding the reference of specimens. It usually occurs in the soft shale, one side adhering to the 
stone, from which it is necessary to remove some portions of the coral before its real character 
can be ascertained. Portions of fronds, six inches or more in diameter in every direction, have 
been obtained, and which are imperfect on all sides, showing that the coral attained a large 
size. 
From the mode of divergence of the frond from a centre, it appears that the perforations are 
arranged in concentric circles, each row or circle having successively been at the outer margin 
of the frond. 
Fig. 5 a. A fragment from a much larger frond. 
Fig. 5 b. A small fragment where the perforations are smaller, though the coral does not ap¬ 
parently differ in other respects from the preceding. 
Fig. 5 c. An enlarged portion of the surface, showing the arrangement of cells in reference to 
the perforations. 
Fig. 5 d. An enlargement where the cells are arranged in series parallel to the axis of the 
branch. 
Fig. 5 e. A section of a branch enlarged, showing arrangement and upward divergence of the 
cells. 
Position and locality. In the shale of the group at Lockport, and very rarely in the lower 
part of the limestone. Macerated fragments sometimes occur associated with Callopora and 
TreMATOPORA. (Collection of Col. Jewett.) 
555. 5. RETEPORA DIFFUSA. 
Pl. XL C. Fig. 1 a - f. 
Fruticulose; several stems originating from a common base; stems frequently bifurcating 
and spreading laterally, forming a broad frond ; stems and branches celluliferous on one side 
only, the other side deeply striated longitudinally; apertures of cells quadrangular or sub- 
rhomboidal, with the angles in the direction of the longitudinal and transverse axes of the stems 
and branches, and sometimes much extended longitudinally; branches often crowded and 
tortuous ; terminations often thickened or clavate, and always obtuse. 
