134 



Professor Agassiz remarked that the folds around the young in 

 these viviparous fishes might be compared to those surrounding the 

 eggs in other cases, and that this might after all be only a modifica- 

 tion of ordinary ovarian gestation. 



Dr. Bryant read a paper on the restricted genus Catar- 

 ractes (Moehring), as follows : — 



Monograph of the Genus Catarractes, Moehring. By 

 Henry Bryant, m.d. 



In consequence of the want of authentic American specimens of 

 this genus, no satisfactory descriptions have been given by any orni- 

 thologist, of the species inhabiting our coasts. Wilson does not 

 describe them at all ; Audubon confounded rlngvia and ti oille ; Nuttall 

 and Swainson did the same, and in the 9th vol. of the Pacific Eail- 

 road Report, the best work yet published on American ornithology, 

 the writer states that he has never seen an American specimen of 

 troille, and describes the Pacific species as ringvia. A few winter or 

 immature specimens of Brunnich's Guillemot have been obtained 

 from time to time, but I am not aware that a single adult in summer 

 plumage has ever been seen on our coast, south of Hudson's Bay, by 

 any ornithologist but myself. Ha-vang had an opportunity of examin- 

 ing a great number of the three Atlantic species of this genus, both 

 living and dead, and possessing a large series of specimens, I have 

 been led to think that a monograph of this genus would be accepta- 

 ble to American ornithologists. In addition to the specimens in my 

 own collection, Professor Baird has, with his usual kindness, allowed 

 me to examine the whole series belonging to the Smithsonian Institu- 

 tion. The different specimens are from the Arctic Ocean, western 

 and eastern coasts of North America, Greenland, Iceland, Faroe and 

 Orkney Islands, and western coast of Europe, and have enabled me 

 not only to describe the American species, but to compare them 

 critically with specimens from many other localities. 



I am sorry to propose any change of nomenclature, but if the law 

 of priority is to be carried out, which has so di&turbed the nomencla- 

 ture of the North American birds in the ninth volume of the Pacific 

 Railroad Report, I do not see how this can be avoided. The family 

 Alcidce of Swainson, should be Plautidce of Klein;* lomvia of Brlin- 

 nicli, should be troille of Linnaeus, and arra of Pallas, lomvia of 

 Linnaeus, f 



Family Plautid^ Klein. 



Ch. Body fiattened ovate, compact and muscular ; plumage very 

 thick and elastic ; bill compressed, higher than broad ; wings short, 



* Klein, Hist. Av. Prod. p. 14G, 1750. Fainilia soplima, I'lautus. Tridactylus, 

 palmijies, di^'ito nullo postico. 



t Linu. Syst. Nat. edition x. 130. Alca lomvia. Uostro hivi obloll^^'0, niaudibulo 

 euperioie marline ttavesceiitt. 



