PROM THE EIO PARAGUAY. 29 



striated, half as long as pectoral spine. Pectoral spine a little longer than the 

 head. Dorsal I 6 ; spine a little shorter than the head, very strongly serrated in 

 front, very feebly behind. Adipose fin a little shorter than base of anal. No shields 

 between the dorsal fins. Lateral shields moderate, their vertical diameter equal to the 

 eye, serrated behind, 26 or 27. Caudal bifurcate. Brown above, whitish beneath ; 

 fins uniform or with small blackish spots. 



Total length 80 millim. 



Several specimens from Descalvados, Matto Grosso. 



This species is named after Prof. C. Eigenmann, the author of the excellent 

 synopsis of South American Siluroid Fishes. It connects the sections Oxycloras and 

 Rhinodoras as defined by that author, agreeing with the former in the serrature of the 

 dorsal spine, with the latter in all other respects. 



31. Rhinodoras kneri, Blkr. 

 Paraguay. 



32. Callichthys asper, Q. & G. 

 Paraguay. 



33. Callichthys pectoralis. (Plate IV. fig. 4.) 

 Callichthys pectoralis, Boulenger, P. Z. S. 1895, p. 525. 



Depth of body 3 J to 3^ times in total length. Head depressed, broader than deep, 

 3| times in total length, without bristles on the sides ; diameter of eye 6 times in 

 length of head, 4 times in interorbital width ; suborbital bone narrow ; occipital bone 

 pointed in front, not reaching frontal fontanelle ; outer barbels half total length. 

 Pectoral spine § length of head, covered with fine bristles, serrated on the inner side. 

 Dorsal I 7 ; spine nearly £ length of head. Anal 15. A pair of large pectoral plates, 

 in contact anteriorly or narrowly separated, their inner borders diverging behind. 

 Shields on body reaching to base of dorsal fins, 23 above and 22 below lateral line ; 

 3 or 4 pairs and 5 to 7 azygos shields between the two dorsal fins. Caudal rounded. 

 Dark brown, with small blackish spots. 



Total length 85 millim. 



Several specimens from Monte Sociedad, Paraguayan Chaco. 



This species is most nearly allied to C. thoracatus, C. & V., and C. longifilis, C. & V., 

 but differs in the larger pectoral plates, in the wide separation between the frontal 

 fontanelle and the occipital bone, and in the smaller number of anal rays. 



34. Callichthys paleatus, Jen. 

 Descalvados, Matto Grosso. 



