BULLETIN OF THE UNITED STATES FISH COMMISSION. 225 



Vol. Ill, ]\o. 15. Washington, I>. C. Sept. 3, 1883. 



2?.-PRELOIIlVAR¥ NOTICE OF THE DEVELOPMENT AND BREED- 

 ING HABITS OF THE POTOMAC CATFISH, AMIURUS ALBIDU8 (EE- 

 SUEUR) GUL. 



By JOHN A. RYDER. 



A number of adult individuals of Amiurus albidus were brought from 

 the Potomac Eiver to the Armory building*, at the instance of Lieut. 

 W. C. Babcock, IT. S. JST., and Col. M. McDonald, and deposited in 

 the large tank aquaria of that institution about the close of the shad 

 fishing season of 1883. One pair of these have since bred or spawned 

 in confinement, and thus afforded the writer the opportunity of observ- 

 ing and describing some of the more interesting phases of the develop- 

 ment of this singular and interesting family of fishes. There has been 

 hitherto little attention paid to the development of the Rematognathi, 

 Siluroids or catfishes, probably from a lack of opportunity, and these 

 notes may therefore prove of interest to naturalists. The literature 

 of the subject is scanty ; and besides a paper by Jeffries Wyman* 

 on the development of Aspredo Icevis and Bagrus, I know of no sep- 

 arate essays on the development of this group, except some scattered 

 notices in Giiuther's Introduction to the Study of Fishes and in his 

 article Ichthyology, ninth edition of the Encyclopaedia Britannica, on 

 the development of Arius ; an egg of this genus in an advanced state 

 of evolution is figured, from which it appears that this form is very 

 similar in its embryological features to JElurichthys, some ova of which 

 are in my possession, measuring three-fourths of an inch in their longest 

 and five-eighths of an inch in their shortest diameter. Arius and JElu- 

 richthys are marine forms, and the males have the habit of carrying 

 the ova in the hinder part of the oral cavity or branchial region until 

 the young are hatched, as redescribed by W. Turner, t The marine 

 species, however, have only a few ova at a time as compared with the 

 Amiuri, common catfishes or horned pouts of the Eastern United States. 



Prof. Theodore Gill has been kind enough to aid me in determining 

 the species of which I here sketch the development, and he refers it to 

 the form with the name given in the title of this notice. Its habits 

 of spawning and care of the young are probably common to all of the 

 species of the genus, and are quite remarkable, as will appear from the 

 subjoined account. 



On the morning of the 13th of July, a little after 10 o'clock a. in., we 



* On some unusual modes of gestation. Am. Journ. Arts and Sciences, xxvii, 1859, 

 pp. 5-13. 



t A remarkable mode of gestation in an undescribed species of Arius (A. Boakcii) 

 Journ. Anat. and Physiol., i, 1866, pp. 78-82. 



Bull. U. S. F. C, 83 15 



