620 BULLETIN 106, UNITED STATES NATIONAL MUSEUM. 



five small elliptical avicularia, little salient, with pivot. The apertura is oval, 

 deeply imbedded at the base of the peristomie; the peristomice is elliptical, elon- 

 gated, not garnished with a peristome. The ovieell 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. 



. lhpe=.:. 

 measurements. 1 enstomice (exterior) 7 



(IpeO.Wmm. 



. |Z3=0.40-0.48mm. 

 Zooecia , n . 



Us=0.30mm. 



Variations. The peristomice may be mistaken for the apertura 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 Kleidionetta parasitica and Kleidionella 

 grandis in the almost complete absence of cumulate zooecia and in its very char- 

 acteristic zoarium. 



It differs from Kleidionetta 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. 



Occun'ence. Middle Jacksonian : Wilmington, North Carolina (very com- 

 mon) ; near Lenuds Ferry, South Carolina (common) ; Eutaw Springs, South 

 Carolina (rare) ; Balclock, Barnwell County, Georgia (rare). 



CotypesCzt. Xo. 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, rhomboidal ; 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 



