262 MEMOIRS OF THE CARNEGIE MUSEUM. 



would dart from its hiding place as I raked my ringers through the sand, to dart 

 into the sand again much like a lancelet or young lamprey, or to dodge under a 

 rock. Mr. E. B. Williamson wrote me that he noticed another species clinging to 

 the vertical sides of a waterfall. It looked like a water-weed, but he found by 

 watching closely that every little while the supposed weed would move up the wall 

 a short distance, and by using his butterfly-net he secured specimens. It is this 

 habit assisted by the opercular spines that accounts for the fact that the species of 

 the genus Pygidium are found in every mountain-stream. 



The habit of insinuating themselves into crevices is undoubtedly also the 

 starting point of the habit of resorting to the gill-cavities and probably other organs 

 of larger fishes. There is a widely distributed belief among the Indians of the 

 Amazon Valley, that fishes called "Candiru" enter the urethras of bathers. Some 

 travelers who have had this habit reported to them have simply dismissed the matter 

 as absurd. Others have made attempts to identify the fish with results that have 

 not always been fortunate. The native name, Candiru, is applied to some fishes 

 (Cetopsis of the Cetopsidce) at least a foot long, and at least two inches thick, as well 

 as to minute slender fishes, species of Vandellia, which might enter the urethra 

 without violating the law that the greater cannot enter the less. The habit has 

 been attributed to the large Cetopsis, to Pareiodon, more moderate in size and yet 

 too large, and to some species of Vandellia and to Acanthopoma. It is, of course, 

 possible that the young of the larger Candiriis have the urinophilous habit. It is 

 also possible that the Indians consider the small Candiriis (species of Vandellia) 

 as the young of the larger Candiriis, members of the genus Cetopsis, which according 

 to the classification adopted, belong to a different family. The habit is also phys- 

 ically possible for the species of Tridens, of Miuroglanis, of Paravandellia, Stego- 

 philus, Branchioica, and for some of the minute species or young of Pygidium. 

 However, these have not been indicated as being Candiriis. As far as I am able 

 to find, the first notice of the peculiar habit is given by Spix (Selecta Genera et Species 

 Piscium, 1829, p. viii), who says of Cetopsis: 



De alio pisce hominibus infesto nonnulla afferre debeo, quern Brasilienses Candiru, Hispani 

 in provincia Maynas degentes Canero nuncupant. Singulari enim instinctu incitatur in ostia 

 excretoria corporis humani intrandi, quae quum igitur in Ms, qui in flumine lavant, attingit, 

 summa cum violentia irrepit, ibeque carnem morsu appetens, dolores, irao vitse periculum affert, 

 Tiinie odore hi pisciculi valde alliciuntur, quam ob causam accolge intraturi flumen amazonum, 

 cujus sinus hac peste abundant, pneputium ligula constringunt, et a raingendo abstinent. Pertinet 

 hie piscis ad Cetopseos, quod depinximus, genus; at nescio, an descriptarum specierum (C. 

 candiru et C. ccecutiens) individua juniora, an tertise cujusdam speciei minoris individua crudeli 

 hoc instinctu a natura sint donata. 



