620 
BULLETIN 106, UNITED STATES NATIONAL MUSEUM. 
five small elliptical avicularia, little salient, with pivot. The apertnra is oval, 
deeply imbedded at the base of the peristomie; the peristomice is elliptical, elon- 
gated, not garnished with a peristome. The ovicell is hyperstomial, little salient, 
convex, transverse, smooth; it opens into the peristomie by a very large opening. 
The interzooecial avicularia are of the size of the zooecia; they have a pivot placed 
quite low ; their beak is round and not salient. The cumulate zooecia are very rare; 
they are globular, oblique, very convex and bear one or two frontal avicularia. 
Measurements. — Peristomice (exterior) 
Ape=0.14 mm. 
lpe= 0.10 mm. 
Zooecia 
T2=0.40-0.48 mm. 
7,2=0.30 mm. 
Variations. — The peristomice may be mistaken for the apertnra in the very 
young zooecia (fig. 4) at the extremities of the fronds. The ovicell is formed rather 
slowly (fig. 4) and is easily broken (figs. 5, 8). The cumulate zooecia are extremely 
rare; they sometimes appear isolated (figs. 5, 9) ; but at other times they are 
grouped (figs. 10, 11) . Their presence, even accidental, proves that this species 
is well classed in its true genus and that it is a Celleporid. 
The olocyst is so compact that it is impossible to obtain its microstructure 
(fig. 12) in tangential section; as in the other Celleporidae the zooecial limits are 
not visible in such sections. 
The longitudinal section shows (fig. 13) short zooecia with thick walls and 
an oblique apertura. 
Affinities. — This species differs from Kleidionella, parasitica and Kleidionella 
grandis in the almost complete absence of cumulate zooecia and in its very char- 
acteristic zoarium. 
It differs from Kleidionella cristata in the fronds of the zoarium, which are 
wider and deprived of median crest. 
Its zoarium often exceeds one centimeter in length, and we may consider it 
as a good-sized fossil. 
Occurrence. — Middle Jacksonian : Wilmington, North Carolina (very com- 
mon) ; near Lenuds Ferry, South Carolina (common) ; Eutaw Springs, South 
Carolina (rare) ; Baldock, Barnwell County, Georgia (rare). 
Cotypes— Cat. No. 64227, U.S.N.M. 
KLEIDIONELLA CRISTATA, new species. 
Plate 77, figs. 12-21. 
Description. — The zoarium is formed of elongated, bilamellar fronds, com- 
posed of two lamellae, back to back; the cumulate zooecia are grouped on the 
zoarial axis, thus thickening it and forming a characteristic longitudinal crest. 
The oriented zooecia are elongated, little distinct, rliomboidal; the frontal is thick, 
little convex, formed of a little compact olocyst; it bears one or two elliptical 
avicularia. little salient with pivot. The peristomice is elongated, elliptical; the 
apertura is oval, very finely denticulated. The ovicell is hyperstomial, transverse, 
salient, convex, smooth; it opens widely into the peristomie. The cumulate zooecia 
