APPENDTX^UYGLOPIUM nVCLoPUM. . 137 



CYCLOPIUM CYCLOPUM, Humboldt. 



By F. day, CLE., F.L.S., F.Z.S. 



I received in Sept. 1883, Mr. Wliyiu2ier'.s collection of these small 

 siluroid fishes, in excellent condition, amounting to 51 specimens, which 

 were ohtained at Machachi (9500), Chillo (8500), neighhourhood of Cayandie 

 (9-9500), and Riobamba (9000).^ The streams from the three first-named of 

 these localities flow into the Pacific, and from the last jiass into the 

 Amazons. 



B. iv., T). i I 0-1, P. -, V. ^, A. A, C. 13. 



I '■• ' 4 ' 0-(i ' 



Length of head about 4| to 5, of caudal fin 4| to 6| in the total length, 

 — among four specimens from Chillo being as follows : — 



Length of spcciinon .3-6 inches ; of head 4i of cauilal fin 5^ in the total length. 



3-0 ,. ,. i> ,, 6| „ 



1"9 M ,, 4| ,, 4f „ 



2-0 ,, ,, 4i ,, 5 



The al)(>ve figures show that a consideral)le individual variation in pro- 

 portions exists. The width of the head as a rule etj^uals its length, but 

 varies from ~ to | of that extent. Eyes small, situated in or slightly behind 

 the middle of the length of the head. Lips thick, broad, especially the lower, 

 and evidently used as a sucker ; nostrils — separated by a well - developed 

 flap — situated one-half nearer the snout than the orbit, and a barltel at the 

 angle of the mouth wliich reaches as far as the orbit. The skin on the U2>per 

 surface of the head rough. Gill -openings separated l)v a broad isthmus. 

 Teeth — in the upper jaw in several rows, the outer of which are flattened 

 and of a club-like form in their outer ends, while the inner rows of teeth 

 have y-like branched outer extremities. In the lower jaw the teeth are larger 



^ As a detailed account of the small siluroid.s of the Andes has been given by Dr. 

 F. W. Putnam (American Naturalist, 1871, p. 694) it will be unnecessary to again go 

 through them at much length. The conclusions there arrived at were formulated from 

 an investigation into a specimen from Quito, Ecuador, and from the descriptions by Dr. 

 Giinther of Arges brachycejjhalus, founded on two specimens from the Andes of Western 

 Ecuador, and Stygogencs Humholdtii, Giinther, described from four specimens up to 

 two inches in length from Madame I. Pfeitfer's collection D. —^ \ 0-1, A. 6, C. 13, 

 P. 8-10, V. 6. 



Putnam suggested that the spine in the second dorsal fin of Humboldt's specimen was 

 overlooked, and also in Dr. Glinther's specimen of Sti/gogenes, but more probably it was 

 atrophied. 



T 



