[ 191 3 



III. A Monograph of the Fishes of the Family Loricariidae. 

 • By C. Tate Began, B.A., F.Z.S. 



Received October 13, read November 17, 1903. 



[Plates IX.-XXL] 



i-HE Loricariidae are a family belonging to the suborder Ostariopbysi, and are found 

 only in the rivers of South America, ranging from Panama and Trinidad or Porto Rico 

 to Montevideo. The Ostariopbysi resemble the Malacopterygii, the most primitive of 

 Teleostean Fishes, in having the air-bladder, if well developed, provided with a duct, the 

 ventral fins abdominal in position, and a mesocoracoid element present in the pectoral 

 arch ; they are, however, distinguished by the modification of the anterior vertebra?, 

 which are usually fused, some of their lateral and superior elements forming a chain of 

 ossicles (ossicles of Weber) connecting the air-bladder with the auditory organ. The 

 Ostariophysi are arranged by Boulenger in 6 families — Characinidae, Gymnotidae, 

 Cyprinidae, Siluridae, .Aspredinidae, and Loricariidae, the last being equivalent to the 

 Siluridae Hypostomatina of Giinther, with the exception of the genera Callichthys, 

 Sisor, Erethistes, Exostoma, and Pseudecheneis, or to the Loricariidae and Argiidae of 

 Eigenmann. 



The Loricariidae share with the Siluridae most of the characters which serve to 

 distinguish that family from the more generalised Characinidae, the most important 

 of which are the reduced maxillary, the absent symplectic and suboperculum, and 

 the union of supraoccipital and parietals to form a single parieto-occipital bone ; 

 but they present certain features of still greater specialisation — such as the absence of 

 parapophyses, the sessile ribs, and the compressed caudal vertebrae — which warrant 

 their separation as a distinct family. 



Most of the fishes of this family can be recognised by the armour of bony plates 

 protecting the body, although the degenerate Argiinae are naked ; the inferior sucker- 

 like mouth is also characteristic 1 . 



It seems not improbable that the Loricariidae may have evolved from the Siluridae 

 in the neighbourhood of the Doradina, which they resemble in many respects. 



1 It appears that in nature these fishes fasten themselves to stones by means of the sucker-like mouth, 

 whilst in captivity they have been observed to adhere to the bottom or sides of the vessel in which they 

 are placed. Eespiration seems then to be effected by taking in water through the gill-openings and 

 expelling it again by the same passages in a reverse direction. 



vol. xvii.— part in. No. 1. — Ocioler, 1904. 2 d 



