96. PTEEYGOPLICHTHYS. 251 



96. PTERYGOPLICHTHYS. 



Ancistri macropteri, K?ier, Denkschr. Acad. Wits. 7Fi'ert,1854,vii.p.256. 

 Pterygoplichthys, sp., GUI, Ann. Lye. Nat. Hist. New York, vi. p. 408. 



This genus agrees in all the characters with Hypostomus, but has 

 the interoperculum armed with erectile spines, and from twelve to 

 fourteen rays in the dorsal fir 



Brazils. 



1. Pterygoplichthys duodecimals. 



Hypostoma etentaculatum, Spix, Pise. Bras. p. 7. tab. 4 (bad). 

 Hypostomus duodecimalis, Cuv. fy Vol. xv. p. 498. pi. 454 (not good). 



brevitentaculatus, Ranzani, Nov. Comm. Aca< 7 Sc. Inst. Bonon. 



1842, v. p. 328. 

 Ancistrus longimanus, Kner, Hypostom. p. 283. 



D. 1/11. A. 5. P. 1/6. V. 1/5. L.lat. 28-29. 



Head not depressed, its length being a little less than one-third of 

 the total (without caudal) ; a rather prominent ridge runs from the 

 eye to below the nostril ; occiput with f rather elevated ridge, scutes 

 of the nape bicarinate. A short barbel on each side of the mouth. 

 Eye small, its diameter being somewhat more than one-fourth of the 

 width of the interorbital space. Intel operculum with a bundle of 

 about seven erectile spines, which are slightly flexible, and curved at 

 the end ; the strongest is a little longer than the eye. Thorax and 

 belly nearly entirely covered with minute imbricate scutes. Dorsal 

 fin much longer than high, the length of its anterior rays being equal 

 to its distance from the caudal ; there are seven scutes between the 

 two dorsal fins. Caudal obliquely truncated ; anal well developed ; 

 thirteen scutes between anal and caudal. The pectoral spine is ex- 

 tremely long and strong, spiny, extending nearly as far backwards 

 as the ventral. Scutes of the body keeled. All parts with numerous, 

 round, closely-set, small brown spots, wlilch are confluent in some 

 places, forming reticulated lines ; they are smallest on the head, 

 largest and surrounded with white on the fins ; they form two more 

 or less confluent series on each interradial space of the dorsal fin. 

 Membrane of the second dorsal fin black. 



Rio San Francisco. 



a. Fifteen inches long : stuffed. Brazil. 



2. Pterygoplichthys punctatus. 



Loricaria punctata, Natterer, MS. 



Ancistrus duodecimalis, Kner, Hypostom. p. 281 (not synon.). 



D. 1/12. A. 5. 

 The length of the head is two-sevenths of the total (without 

 caudal) ; occiput with a slight longitudinal prominence. The dia- 

 meter of the eye is two-sevenths of the width of the interorbital 

 space. Interoperculum with a few erectile spines. Scutes of the body 

 keeled ; lower parts covered with small shields. Barbels longish. 

 There are six scutes between the two dorsal fins, and thirteen be- 

 tween anal and caudal. The pectoral spine extends a little beyond 



