BRYOZOA. 551 



FEXESTELLA PERMINUTA Ulrich. 



PL LH. Fig. 4-lb. 



Zoarium an exceedingly delicate small expansion, growing 

 from a spreading foot stalk into a remote resemblance to Ptilo- 

 pora. From both sides of the central stem two branches spring 

 out at a rather acute angle. These are very slender, bifurcate 

 at short intervals, and are 0.15 mm. in width. Dissepiments 

 long, extremely slender, at first about equal in number to the 

 bifurcations. Fenestrules of variable shape, averaging 0.5 bv 

 0.3 mm. Carina very little developed, almost obsolete. Zooecia 

 apertures in two alternating rows, circular, prominent, project- 

 ing decidedly beyond the margin of the branch, more than twice 

 their diameter apart, with twelve in 3 mm. On the reverse the 

 branches are finely striated. 



The extreme delicacy of the zoariurn, in which the species is 

 not equalled by any other known to me, and the projecting 

 cell-apertures, are regarded as the principal peculiarities. 



Position and locality: Coal Measures, Seville, 111. 



> 



FENESTELLA WORTHENI Ulrich. 



PI. LH, Fig. 5-5a. 



Zoarium a small, delicate, fan-shaped expansion. Branches 

 comparatively strong, about twelve in 5 mm., each 0.25 mm. 

 in width. Dissepiments about half as wide as the branches, 

 rounded and widening considerably at the ends. Fenestrules 

 sub-quadrangular, indented a little on each side, about 0.3 by 

 0.2 mm. and twelve in 5 mm. Carina very strong, sub-cylindri- 

 cal or thread-like, about half as thick as the entire branch. 

 Along the middle of the carina there is a row of small nodes, 

 (their apical opening is better preserved than usual), distant 

 from each other about 0.15 mm. Zooecia in two ranges, twenty- 

 four in 1 cm. Apertures small, circular, almost three times 

 their diameter apart, situated one at the end of each dissepi- 

 ment and one opposite the middle of each fenestrule. Peristome 

 indistinct. Reverse not seen. 



