FISHES OP THE FAMILY LORICARIID.E. 225 



B. Interoperculura armed with bristles; length of mandibular ramus less than interorbital 

 width. 



1. Dorsal with I 7 rays. 



a. Length of base of dorsal nearly equal to its distance from the caudal. 

 Interorbital width 3A-3i times in the length of head; caudal peduncle 



2\ times as long as deep 27. A. barbatus C. & V '. 



Interorbital width 4 times in the length of head ; caudal peduncle 



2§ times as long as deep 28. A. depressus Gthr. 



b. Length of base of dorsal nearly equal to its distance 



from the adipose fin 29. A. guentheri Rgn. 



2. Dorsal with I 9-10 rays. 



D. I 9. 24 scutes in a longitudinal series 30. A. angulicauda Stdr. 



D. I 10. 25-27 scutes in a longitudinal series 31. A. parahybce Eigenm. 



1. Amcisteus annectens, sp. n. (Plate XI. fig. 2.) 



Depth of body 4f— 5 times in the total length, length of head about 3^ times. 

 Head l-§— 1-jt times as long as broad and \\- If times as long as deep. Diameter of 

 eye 7-8 times in the length of head, interorbital width 1\- 2f times, length of snout 

 If times. Length of mandibular ramus 3 times in the interorbital width. Snout 

 narrowed anteriorly ; supraoccipital with strong median ridge ; supraorbital edges 

 raised; temporal plates carinate ; interoperculura. armed with 5 or 6 slender spines, 

 the longest equal to -g- the length of head. Scutes spinulose, the anterior and upper 

 ones carinate, 26-27 in a longitudinal series, 7-8 between dorsal and adipose fin, 

 13 between anal and caudal. Supraoccipital bordered posteriorly by a median scute 

 and by one on each side ; two series of scutes between the nuchal and posthumeral 

 series. Lower surface of head and -abdomen completely covered with small granular 

 scales. D. I 7, the first ray equal to the length of head, the last \ as long ; length of 

 base of dorsal greater than its distance from the adipose fin. A. I 4. Pectoral spine 

 extending beyond base of ventral. Caudal emarginate, the outer rays produced. 

 Caudal peduncle 3-g— 3-j times as long as deep. Dark spots on head, body, and fins; 

 dorsal with a series of especially large and distinct spots, one at the base of each 

 interradial membrane. 



Total length 280 mm. 



Two specimens from St. Javier and the Rio Durango, N.W. Ecuador, collected by 

 Mr. Rosenberg, referred by Boulenger to Plecostomus bicirrhosus. 



I have given this species the name " annectens " because it has the general form 

 of Plecostomus guacari and of the species of the old genus PterygopLchthys, and 

 whilst agreeing with the former in the number of dorsal rays, has the movable inter- 

 operculum of the latter. 



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