BRYOZOA. 503 



mm. in diameter with unequally elevated peristome; arranged 

 in more or less regular diagonally intersecting series, about 

 eight in three mm. Interspaces slightly concave, wider than the 

 diameter of the apertures. 



The remarkable zoarial habit of this species distinguishes it 

 from D. flabellum Rom. and D. elegans, its nearest congeners. 

 The silicified specimens upon which the species is founded were 

 collected six or seven years ago by Prof. A. G. Wetherby, and 

 kindly presented to the author. After a cursory examination 

 at the time, I laid them aside under the supposition that they 

 were nothing more than a species of Lyropora encrusted by 

 some Fistuliporoid. A more careful second examination has re- 

 sulted in a very different conclusion. 



The thickened support is comparable to the solid base of 

 Evactinopora M. & W. 



Position and locality: St. Louis group. Southern Kentucky. 



ACTINOTRYPA Ulrich. 



(For generic diagnosis see page 386.) 



ACTINOTRYPA PECULIARIS Roinmger. 



PL LXXVH, flg. 3, 3b. 

 Fistulipora peculiaris Rominger, 1866. Proc. Acad. Nat. Sci. Phila. p. 123. 



Zoarium a thin bifoliate expansion, several cm. in height and 

 breadth, and from 0.5 to 2.5 mm. in thickness. Surface even, 

 provided with subcircular broad maculae, appearing minutely 

 punctured when a little worn, but granular when well preserved. 

 Macula? level with the general surface, occurring at rather vari- 

 able intervals, but an average distance of about six mm. pre- 

 vails. Apertures regularly arranged in diagonally intersecting 

 series, about six in three mm., floriform, owing to the tooth- 

 like projections of the internal ridges, with raised peristomes; 

 about 0.25 mm. in diameter, those nearest the maculae a little 

 larger. Interspaces of equal or somewhat less width than the 

 diameter of the apertures. Zooecia at first prostrate, then bent 

 outward almost at right angles. Occasionally the angle at the 

 point of bending is prolonged into a short superior hemi.sep- 



