BRYOZOA. 431 



LEIOCLEMA FOLIATUM Ulrieh. 



(Fig. 1, page 301.) 



Zoarium a delicate laminar expansion, from one-half to one 

 and a half mm. in thickness, with a thin wrinkled epitheca on 

 the under surface. Upper surface even, spinulose, with a hirsute 

 appearance. Zooecia, except at their origin, direct, with thin 

 walls, about six in the space of two mm. Apertures circular, 

 petaloid, about 0.2 mm. in diameter. Mesopores small, angu- 

 lar or subcircular, arranged in a single, occasionally a double 

 row about the zocecia. Diaphragms thin, few and remote in 

 the zooedal tubes, rather more than their own diameter apart 

 in the mesopores, sometimes apparently wanting even in these. 

 Acanthoporcs very large and prominent, usually three, some- 

 times four, surrounding each zooecium and projecting more or 

 less into its cavity. 



The laminar form, less numerous acanthopores, and compara- 

 tively small number of mesopores. distinguish this species from 

 the L. punctatum, occurring in the same beds. 



Position and locality: Warsaw beds, Warsaw, 111. 



LEIOCLEMA? ARAXEUM Ulrieh. 



PL LXXV, Fig. *-3c. 



Zoarium consisting of a thin crust, about one-half mm. in 

 thickness, attached to foreign bodies, sometimes throwing up 

 small, short branches. Surface generally even, sometimes marked 

 with small, pointed tubercles. Zooecia arranged radially about 

 one or more centers; at first prostrate, soon proceeding directly 

 to the surface, nine or ten in the space of two mm., sometimes 

 in contact, at other times separated by mesopores. Apertures 

 oval, their longer diameter scarcely 0.2 mm. Mesopores small, 

 irregular in shape, frequently compressed between the zooecia, 

 scattered about rather promiscuously, commonly aggregated 

 into clusters, which are often elevated into conical monticules, 

 appearing subsolid at the surface. Diaphragms closely set in 

 the zooecial tubes, about three in the space of a tube diameter, 

 a little more closely set in the mesopores. Acanthopores very 

 small, situated in the wall of the zooecium, with from seven to 

 ten encircling each zouecium. 



