Miscellaneous. 95 



One of the most curious zoological facts connected with the sub- 

 marine terrace is the presence of an immense bank of living Avicidce 

 (Avicida tarentina, Lamk.), situated 4 leagues out to sea from the 

 opening of the basin of Arcachon, at depths of 40 to 50 fathoms. 

 This bank is prolonged to the south opposite to the light of Mimi- 

 zan (Landes) and northwards opposite Hourtins (Gironde). Its 

 length is estimated at 25 leagues, and its Tv'idth at 1 league ; it is 

 not perfectly continuous, but is interrupted here and there. The 

 fishermen of Rochelle, whom I have interrogated upon this subject, 

 assert that it is met with again above the mouth of the Gironde, and 

 that it may be traced towards the north-west as far as the rock of 

 Rochebonne across the isle of Re. 



Many fishes approach the bank of Aviculce ; the fishermen, there- 

 fore, throw in their nets as near to it as possible ; but it frequently 

 happens that they lose them or are obliged to draw them in loaded 

 with Aviculce. 



The formation of analogous banks is common among the byssi- 

 ferous Mollusca (Mytilus, Meleagrina, Dreissena) ; the great strength 

 of the byssus of the Aviculce explains the great cohesion and the 

 extent of their colonies. — Comptes Rendus, November 16, 1868, 

 pp. 1004-1006. 



Notice of a new and diminutive species of Fossil Horse (Equus parvu- 



lus), from the Tertiary of Nebraska. By Prof. O. C. Marsh, of 



Yale College. 



In a small collection of fossil vertebrate remains, obtained by the 

 writer during the past summer in the Tertiary deposits of Nebraska, 

 there are several specimens of no little interest, as they indicate a 

 new species of fossil horse, very much smaller than any hitherto 

 known. These remains were collected at Antelope station on the 

 Union Pacific Railroad, about 450 miles west of Omaha, where a 

 few weeks before, during the excavation of a well, they had been 

 thrown out from a depth of sixty-eight feet. This locality has since 

 attained considerable notoriety from the fact that the remains then 

 found were pronounced to be human by those who first examined 

 them, and various accounts of the discovery have been published in 

 the newspapers. This, in fact, induced the writer, when in the 

 vicinity, to examine the locality and its fossils, an account of which 

 he has already given elsewhere *. 



The equine remains now to be noticed consist mainly of bones of 

 the limbs ; and among them is a hoof-phalanx, a coronary or second 

 phalanx, parts of the first phalanx and metacarpals, as well as some 

 of the smaller carpal and tarsal bones, and fragments apparently 

 from other parts of the skeleton. All are in an excellent state of 

 preservation, and part of them are so characteristic that they clearly 

 indicate the near affinities of the animal to which they belonged. 



The ungual or hoof-phalanx differs in form from that of the 

 recent horse only in being somewhat more depressed, and in having 



* National Academy of Sciences, Northampton Meeting, Aug. 1868. 



