Pal^ophycus congregattjs. (N. sp.) 



Description. — Stems cylindrical, from one to four lines in diameter, often 

 crowded together in such abundance as to completely cover the surface of 

 the rock. They lie across each other in every direction, and appear to be 

 so interlaced that where very thick the same stem can seldom be traced 

 for more than one inch in length. They are either straight or crooked, 

 and sometimes present sudden slight enlargements of the diameter, giving 

 them a somewhat nodulose aspect. 



Locality and Formation.— One mile south of the boundary line, on the 

 road leading from Moor's Corners in St. Armand to Saxe's Mills in High- 

 gate, Vermont. In the thin beds of the Potsdam group. Red sandrock 

 formation of Vermont. 



Collector. — E. Billings. 



PROTOZOA. 



In the limestone at Anse au Loup there are numerous fossils which 

 from their radiated structure have the aspect of true corals, and yet in 

 polished sections seem to possess the poriferous organization of sponges. 

 I shall therefore leave it an open question as to which of the two divisions 

 they should be referred. There appear to be two closely allied genera, 

 but for the present I shall place all the species in one. 



[Since the above was written I have, in 1864, ascertained by treating 

 a silicified specimen of A. Minganensis with acid that it contains numer- 

 ous silicious spicula, and these fossils must, therefore, be classified among 

 the extuict tribes of sponges.] 



Genus Aecheocyathus. (N. gen.) 



Generic characters. — Turbinate simple or aggregate ; cup deep. The 

 internal structure, so far as can be made out, consists of an inner wall 

 constituting the inner surface of the cup, and an external wall or epitheca 

 enveloping the whole. Between the two walls there are numerous radia- 

 ting septa, the interseptal spaces being filled with poriferous or cellular 

 tissue. It is highly probable that the inner wall is permeated by pores 

 communicating with the interseptal tissue. 



[The radiating septa are, in A. profundus, perforated with small pores. 

 The spicula found in A. Minganensis are slender, fusiform, shghtly 

 curved, acute at both extremities.] 



In A. Atlanticus the radiated structure is not so well defined as it is 

 in the others, but still it can be observed in the pohshed sections. In 



