BRYOZOA. 119 



Proboseina.] 



Genus PROBOSC1NA, Audouin. 



Proboseina (part.), AUDOUIN in Savigny, Desc. de 1'Egypte, Pol., p. 236, 1826. 



Proboseina, d'C-RBiGNY, 1852, Pal. Fr. terr. cret., t. v, p. 844. HAIME, 1854, Bry. de la form. Jurass., 



p. 10. Ulrich, 1882, Jour. Cin. Soc. Nat. Hist., vol. v, p. 149, and 



1890, Geol. Sur. 111., vol. viii, p. 368. 

 Not Proboseina, of SMITT and others. 



Zoaria wholly adnate. Zocecia as in Stomatopora, excepting that they are more 

 or less immersed and not uniserial, being arranged in two or more contiguous rows. 

 For remarks relating to this genus see under Stomatopora. 



PROBOSCINA TUMULOSA, n. sp. 



PLATE I, FIG. 24. 



Zoarium adnate, branching dichotomously, or inosculating, in the latter case 

 forming an irregular large-meshed network. Branches narrow, generally with two 

 or three, rarely four or five, alternating series of cells. Zooecia subpyriform, or 

 obovate, not wholly immersed, generally appearing as bulbous swellings on the sur- 

 face of the zoarium. Apertures subterminal, contracted, circular, slightly oblique, 

 about 0.09 mm. in diameter, with a slight peristome. About five or six cells in 

 3.0 mm. 



Compared with Proboseina frondosa (plate I, fig. 28) and P. auloporoidea (both 

 Nicholson, sp.), two Hudson River forms, this species is distinguished by its shorter 

 and more bulbous zooecia, their shape being more like those of Stomatopora inflata 

 and Berenicea minnesotensis . The resemblance to the last is so marked that I would 

 not be surprised if coming discoveries prove P. tumulosa directly descended from it. 



Formation and locality. Rare in the upper third of the Trenton shales at St. Paul ; more abundant 

 in the same beds near Cannon Falls, Minnesota. 



Mus. Reg. Nos. 7620, 8047, 8101. 



PROBOSCINA FRONDOSA Nicholson. 



PLATE I, FIG. 28. 



Alecto frondosa NICHOLSON, 1875. Pal. Ohio, vol. ii, p. 266. 



Proboseina frondosa ULRICH, 1889. Contri. to the Micro-Pal, of Canada, pt. ii, p. 28. 



A figure, taken from an excellently preserved example of this species, is intro- 

 duced for the better understanding of, and comparison with, Minnesota Cydostomata. 

 This specimen is from the hill quarries at Cincinnati, Ohio, but the species also occurs 

 in the upper beds of the formation at many localities in Ohio, Kentucky and Indiana, 

 at Nashville, Tennessee, Wilmington and Savannah in Illinois, and at Stony Moun- 



