28 GEOLOGICAL AND NATURAL HISTORY SURVEY OF CANADA. 



DESCEIPTION OF SPECIES. 

 POLYZOA. 



Proboscina auloporoides, Nicholson. 

 Alecto auloporoides, Nicholson. 1875. Pal. Ohio, vol. 2, p. 267, pi. 25 figs. 2-26, 



The collection affords a small and rather badly preserved fragment 

 of a species of Frohoscina indistinguishable from J^icholson's Alecto 

 auloporoides. The cells are mostly uniserial, or rather alternating 

 biserial, without, however, having their sides exposed, the outer mar- 

 gins of the adnate zoarium forming a nearly straight line. The 

 zooecia, consequently, are to be regarded as '' immersed," the same as 

 in P. frondosa. Nicholson, sp., and the typical species of Proboscina. 

 This immersion of the zooecia is the character relied upon in separat- 

 ing the genus or sub-genus Proboscina from Stomatopora, the true species 

 of the latter having the sides of their cells exposed and the margins 

 of the zoarium conforming to theif shape. Of Silurian species S. Prou- 

 tana, S. A. Miller, S. arach7ioidea, Hall, and >S'. elongata, Vine, are true 

 species of Stomatopora. 



Species of the nature of P. auloporoides and P. frondosa are, in my 

 opinion, more nearly related to Berenicea than to Stomatopora^. In 

 comparing numerous species, it becomes a matter of no small difficulty 

 to determine where Proboscina should end and Berenicea begin. On the 

 other hand, the non-immersed condition of the zooecia and their strictly 

 uniserial arrangement in Stomatopora furnishes us with two characters 

 that, so far as my observation is concerned, enable us to distinguish 

 readily enough between Proboscina and Stomatopora. 



Stony Mountain, T. C. Weston, 1884. This species also is not un- 

 common in the middle beds of the Hudson Eiver or Cincinnati group, 

 at Cincinnati, Ohio, and other localities in the United States where 

 these beds are exposed. 



Proboscina frondosa, Nicholson. 

 Alecto frondosa, Nicholson. 1875. Pal. Ohio, vol. 2., p. 266, pi. 25, figs. 3-36. 



This form is likewise represented by but a single example. It is of 

 the typical variety, and, though a little worn, preserves here and there 

 the minute perforations in the walls of the zooecia. The latter occur 



* Berenicea of Lamoureux, Haime, Reuss and Zittel, not of Busk, Hincks and Vine, who, con- 

 trary to accepted rules of nomenclature, use Diastopvra instead. Lamoureux originally proposed 

 Berenicea for incrusting forms of the type of B. diluviana, while Diastopora. was applied by him 

 to the erect double-leaved forms typified by his D. foliacea. 



