BRYOZOA. 531 



The erect form of growth and acute angle of bifurcation, 

 thinner walls and narrower non-celluliferous margins distin- 

 guishes this species from T. ramulosa. 



Position and locality: St. Louis group; Elizabethtown, Ky. 



PTILOTRYPA Ulrich. 



(For generic diagnosis see page 398.) 



PTILOTRYPA OBLIQVATA Ulrich. 



PL XXX, Fig. l-le. 



Zoarium consisting of frondescent branches varying consider- 

 ably in height, width and thickness: the extremes of thickness 

 noticed are 1 and 6 mm, The material at hand, though abund- 

 ant, is not sufficient to determine the nature of the basal at- 

 tachment. My judgment, however, would say that the basal 

 portion was in Tteniodictya and not jointed as in Ptilo- 

 dictya. Surface smooth. Zooecial tubes almost straight in 

 their course from the median laminae to the surface with which 

 they form an angle of between 25 and 40. Apertures lanceo- 

 late, rounded and with an elevated margin posteriorly, acute 

 and drawn out trough-like at the upper end. At irregular inter- 

 vals the surface presents spots where the apertures are more 

 than usually drawn out; they have a striated appearance and 

 simulate maculae. In the spaces between these spots the aper- 

 tures are ranged in vertical series, separated in this direction 

 by an interspace equal or greater than their longitudinal diame- 

 ter which is about 0.25 or 0.30 mm.; in the diagonal series 

 they approximate quite closely .the slight peristomes being sepa- 

 rated by only a narrow channel; measuring diagonally there 

 are about seven in two mm. At the upper end of each zooecium, 

 or in the interspace above it, is found an accessory pore. An 

 occasional complete diaphragm crossing at right angles is 

 found in most of the zooecial tubes. The walls of the tubes 

 have a very curious structure as shown in longitudinal and 

 transverse sections (fig. Id and 1 e.). 



