G4 ^Ir. C. T, Regan on the South- American 



more slender dorsal spines (the last ;•? the length of head) 

 and produced soft fins (except the pectoral), the soft dorsal 

 and anal extending to the posterior part of caudal, the ventral 

 to posterior part of anal, and the middle caudal rays being 

 from more tiian V to nearly ^ the length of the fish (without 

 caudal) ; in the females the last dorsal spine is .} the length 

 of head, the soft fin does not extend beyond the middle of 

 caudal, the ventral reaches the anal spines, and the middle 

 caudal rays are .\ to less than ^ tiie length of the fish. 

 Upper course of the Paraguay. 



1-4, ("Jo-oo ram.) types of Ciuandasiuho, Matto l)r. A. Borelli, 



the species, Grnsso. 



5-7, (35-44 mm,), Colouia Risso. Dr. A, Borelli 



4. Htteroyramma commbra *. 



Mcsopx tceniatus (part.), Bouleng. Boll. Mas, Toriii. x. 1895, no. 196, 



.P- '^^- 

 Btotodoina comynhrce, Eigenm., M.S, 



Depth of body 2^-2| in the length, length of head 2|-3. 

 Snout shorter than eye, the diameter of which is 2':,— 2}^ in the 

 length of head, iuterorbital width 3 j-3?. Depth of praeorbital 

 \ the diameter of eye. Maxillary extending to below 

 anterior margin of eye; jaws equal anteriorly ; fold of the 

 lower lip continuous ; cheek with 3 series of scales ; no 

 scales on the pra^operculum; no distinct gill-rakers on the 

 lower part of anterior arch. Scales 23-24 ^ ; upper lateral 

 line fully developed on 5 to 10 scales only; lower lateral 

 line rudimentary or absent. Dorsal XVI 5-6, the spines 

 subequal from the fourth, the la-^t ^ the length o£ head. 

 Anal III Q)-7 (in one specimen IV 5). Pectoral a little 

 shorter than the head. Caudal rounded. Caudal peduncle 

 |-i as long as deep. Brownish, with darker cross-bars 

 forming a series of blotches below the dorsal fin ; a con- 

 tinuous dark stripe from eye to base of caudal, forming a 

 largo blotch on the caudal peduncle ; each series of scales of 

 the lower part of the boily with a more or less distinct dark 



* In replv to a query asking whether the number of spines in the 

 dorsal fin of Biotodoma trifusciatum had been correctly .stated, Prof. 

 Ei^enmann kindly wrote to me that the type has IG dorsal spines. He 

 also sent me photogi-aphs of the three Paraguayan species of this genu.s, 

 viz. H. Borellii (named by him B. t<enia.tu)ii), II. trifusciatum, and the 

 present species, named li. commbrce, which I had intended de.5cribing 

 under another name. I have kept back this paper in the hope that his 

 memoir containing the descriptions of these species might be publi.shed ; 

 but this not having occurred, I have taken his name for this species, 

 which should be called //. connnbra, Eigenm. 



