438 BULLETIN 106, UNITED STATES NATIONAL MUSEUM. 



Measurements. Apertura f hn=0.15 mm. Peristomice 1 #/?*>= 0.20 mm. 



(interior) 1 70=0.15 mm. (exterior) \ 7pe=0.l5 mm. 



. rZs=d.75-0.85 mm. 

 Zooecia i, rt ... 



lfe=0.45 mm. 



Variation ft. The peristomice is somewhat round with the avicularium adja- 

 cent. When the rimule-spiramen is much developed, there are no avicularia. The 

 two occurrences may be observed on the same zoarial fragment. The lateral tongues 

 are quite variable in form and size. 



Affinities. This species differs from E ' noplostomella deflxa in its very long 

 avicularium (0.40 and not 0.25mm.) and in the tongue-like processes of the peri- 

 stomice. 



It differs from Enoplostomella rho-mboidalis in its zooecia separated by fur- 

 rows and not by prominences, and in its much more globular and salient ovicells. 



Occurrence. Vicksburgian (Red Bluff clay) : Seven and one-half miles south- 

 west of Bladon Springs, Alabama (very common). 



Cotypes.C-At. No. 64292, U.S.N.M. 



ENOPLOSTOMELLA VALLATA, new species. 



Plate 92, tigs. 1-10. 



Description. The zoarium is free, bifurcated, compressed, formed of three or 

 four longitudinal rows of zooecia arranged on one side; on the dorsal face the 

 zooecia are separated by projections or stockades and ornamented with tremopores. 

 The zooecia are elongated, rectangular, separated by projections; the frontal is 

 convex, thick, formed of a tremocyst with tubules surmounting a perforated olocyst. 

 The apertura is very oblique and semilunar with a straight proximal border; the 

 peristomice is somewhat elongated and is provided with a wide and triangular 

 rimule-spiramen. The avicularium is placed on the border itself of the rimule- 

 spiramen, which it bounds laterally; it is triangular and provided with a pivot; 

 the beak is turned outward. 



Measurements. Apertura f ha=0.l-2 mm. . f hpe=Q.20 mm. 



. . \ 7 .Peristomice \ , 



(interior) 1 /=0.15 mm. [lpc=0.1S mm. 



. rZz=0.85-0.95 mm. 

 Zooecia 7 . 



I fe=0.45 mm. 



Width of branches=0.85-1.00 mm. 



Variations. The projections which bound the zooecia on the two faces of the 

 zoarium are not constant; certain branches are deprived of them (figs. 5, 6). 

 However, on the dorsal face, the two lateral rows are alone visible ; on account of 

 their alternate arrangement they appear irregular on the transverse section (figs. 

 7, 8) and only one may be visible (fig. 9). The tubules are longer on the dorsal 

 of the zoarium (fig. 10). We have never been able to discover the ovicell on any 

 of our numerous specimens. 



Affinities. This species is not vinculariform, as are the other species of the 

 same genus previously described. The zooecia are arranged on but one side of the 



