ART. 14 FOSSIL AND KECENT BEYOZOA OANU AND BASSLER 125 



Family STOMACHETOSELLIDAE Canu and Bassler, 1917 

 Genus CIGCLISULA Canu and Bassler, 1927 



CIGCLISULA SERRULATA Smitt, 1873 



Plate 20, Figures 1-14; text Figure 24 



1873. Porina serrulata Smitt, Floridan Bryozoa. Kongl. Svenska Veten- 

 skaps-Akademiens Handlingar, vol. 11, p. 27, pi. 5, figs. 116-125, 



,, ^ -o • ^ • J^i? = 0.10-0.12 mm. 



Measurements. — reristomicei , _ ._ _ .^ 



Up = 0.10-0.12 mm. 



„ . /. ^ • JLz = 0.60-0.65 mm. 

 Zooecia (mterior) , 



Us = 0.25-0.30 mm. 



Structure and variations. — The zoarium is bilameilar; the fronds 

 are narrow and bifurcate like the horns of a deer. The base is cir- 

 cular, little expanded, concave; it appears, therefore, to attach itself 

 to small algae. 



The marginal zooecia are distinct, elongated, covered with tubulai 

 tremopores; the peristome is very sahent, irregularly crenulated. 

 They are transformed sometimes into large spatulate avicularia. The 

 terminal zooecia of the fronds have also the same aspect. All the 

 axial zooecia are indistinct and their frontal is ornamented with a 

 complicated system of avicularia. The large spatulate avicularia give 

 to the fronds the serrulate aspect characteristic of the species. They 

 are inconstant and belong to the group of zoarial avicularia. 



The ovicell is hyperstomial, opening into the peristomie above the 

 operculum, developed between the olocyst and the tremocyst of the 

 distal zooecium. It is not entirely covered over by the tremocyst; 

 on its median longitudinal axis there is a narrow cribriform area 

 formed by a double row of very short costules very variable in aspect. 

 It is little apparent and immersed into the great thickness of the 

 tremocyst. 



The spiramen is very apparent on the young cells, on the marginal 

 cells, and on the little calcified fronds. On the axial cells it is much 

 less apparent and often difficult to observe. In longitudinal section 

 it appears oblique and opens into the peristomie. According to Smitt, 

 it is not covered by the ectocyst, which proves its hydrostatic function. 



The small apertural avicularia are elliptical, with pivot, the beak 

 tm-ned toward the aperture. They are generally placed on the dis- 

 tal arch of the peristome. There is never more than one or two to 

 a zooecium. Small analogous avicularia are developed sporadically 

 on the frontal. 



Large spatulate zooecial avicularia are placed obliquely on the 

 frontal of all the axial zooecia; they are oval, variable in direction, 

 the beak oriented toward the base. The distal orifice is small, oval, 

 marginated. There is no proximal orifice, for the latter is closed by 



