466 BULLETIN 106, UNITED STATES NATIONAL MUSEUM. 



Variations and affinities. The young zooecia (fig. 21) have thin margins and 

 the ovicell is quite, salient. The old zooecia are covered by the pleurocyst; the 

 areolae are larger and the ovicell is immersed in the cap (fig. 23). 



The present species differs from Smittina telum in which the zoarium is 

 identical, in the absence of a large frontal avicularium and in the presence of a 

 lyrula. 



It differs from Sinitt'nm rctic'uloides, which is also provided with large 

 costules, in its much larger micrometric dimensions and in the absence of the oral 

 avicularium. 



Occurrence. Vicksburgian (Glendon member of Marianna limestone) : West 

 bank Conecuh River, Escambia County. Alabama (rare). 



Cotypcs.Czt. No. 64298, U.S.N.M. 



SMITTINA AMPLA, new species. 



Plate 93, figs. 10-16. 



Description. The zoarium is an Eschara in which the two lamellae, back to 

 back, are inseparable. The zooecia are large, distinct, elongated, elliptical; the 

 frontal is very convex and bordered with a line of large triangular areolae; it is 

 formed of an olocyst partially perforated with large lateral pores, surmounted by 

 a pleurocyst with large interareolar costules. The apertura (interior) is elliptical, 

 transverse and bears a small lyrula, cylindical and salient; the peristome is thin, 

 sharp, little salient, garnished with 4 thin spines ; the peristomice is elongated ellip- 

 tical or oval. The ovicell is large, globular, salient, carinated; it is formed of a 

 smooth area surrounded by a salient collar; it covers much of the peristomice 

 which it deforms; it is hyperstomial and opens largely into the peristomie. The 

 oral avicularium is small, elliptical, very salient, deforming inferiorly the peri- 

 stomice. At the side of the apertura there is often a large lateral avicularium, 

 with pivot and a spatulate beak directed towards the top. 



>, . fAa 0.18mm. . f Ae=0.30mm. 



Measurements. Apertura Peristomice , f 



Ua=0.20 mm. l7/?e=0.22mni. 



. (3=0.90-1.00 mm. 

 Zooecia s, 



U3=0.22mm. 



Variations. The lyrula. seen from the interior (fig. 14) appears short and 

 cylindrical; on the exterior (fig. 11) it appears flat and broad. But the interest of 

 this species is in its calcification (fig. 14) ; there is here as it were a juxtaposition 

 of the olocyst and of a tremocyst; the latter only exists at the base of the zooecia; 

 on the sides the line of the areolae become unique. This augmentation of the 

 number of the areolae appears to correspond with a more intense pleurocystal cal- 

 cification. There appears therefore to be a relationship between the tremopores 

 and the areolae, both allowing the buds of the endocyst and the mesenchymatous 

 fibers to pass at the same time. 



The vertical section (fig. 16) shows how the apertura is oblique on the zooecial 

 plane. 



