ART. 14 FOSSIL AN-D EECENT BRYOZOA CANU AND BASSLEE 17 



Genus QUADRICELLARIA D'Orbigny, 1851 



The zoarium is articulated by segments. The zooecia are mem- 

 braniporoid and arranged on four faces (of which two are narrower) 

 placed back to back. No ovicell. 



Genotype. — Quadricellaria elegans D'Orbigny, 1851. Quadricellaria 

 caraibica, new species here described, may be considered as a recent 

 genotype. 



Range. — Cretaceous (Turonian), Recent. 



Affinities. — The discovery in the present seas of this old genus is 

 very important; it shows the great vitality of the genera of the group 

 Ascophora or of the Flustrines as the old authors wrote it. Origi- 

 nating as far back as the Cretaceous, they persist still in the equa- 

 torial zone of the recent seas. Jullien, 1881, classed most of the 

 Cretaceous species of Quadricellaria in his genus Smittipora but 

 D'Orbigny's name has priority. 



The number of specimens obtained is not large enough for us to 

 affirm definitely the absence of ovicells. While waiting more infor- 

 mation, it appears best to introduce this genus into the group of 

 Membraniporae without ovicell. 



QUADRICELLARIA CARAIBICA, new species 



Plate 2, Figures 1-3 



Description. — The zoarium is bushy, radicelled, formed of numer- 

 ous articulated, dichotomous branches; the segments are rectangular 

 and formed of four longitudinal series of zooecia arranged back to 

 back and of which two are wider. The zooecia are distinct, very 

 long, subrectangular with a convex distal border; the mural rim is 

 thin and little salient, complete. The opesium is semielliptical, 

 very elongated, with a straight proximal border; the cryptocyst is 

 shallow, flat, smooth, longer than the opesium. The opercular valve 

 is small, entirely adjacent to the mural rim. 



-,, , -r . f^o = 0.20 mm. 



Measurements. — Large opesiai, „.„ 



^ ^ Uo = 0.10 mm. 



T . \Lz = O.QO mm. 



Large zooecia] 



lis = 0.30 mm. 



Structure. — The zooecium which terminates a segment and which 



bears the two new branches is very convex in its distal portion, 



which gives it the aspect of a false ovicell. The ectocyst covers all 



the zooecium and is terminated by the opercular valve, which is the 



constant structure in the Membraniporae. The cryptocyst is inclined 



toward the opesium, so that the mural rim enlarges into two small 



lateral facettes. All of our segments came from the same colony, 



which was without ovicells. 



58513—28 2 



