Joi'dan and Evermann. — Fishes of North America. 



2057 



with 3 pairs of very strong backwardly directed spines in line with the 

 greatly expanded preopercular ridge; the posterior portion of this ridge 

 produced into a compressed, bluntish process which overlai^s the sub- 

 opercle and reaches margin of gill oijeniug ; opercular aud temporal ridges 

 low and sharp. Teeth present on jaws in the young, becoming nearly or 

 quite obsolete in adults; in the type, 17 cm. long, a few weak teeth on 

 one side of upper jaw, but none elsewhere; vomer and palatines toothless. 

 A cluster of 14 barbels on each side of lower surface of snout in front of 

 mouth, and a cluster of 14 occupying end of maxillary and angle of 

 mouth; each side of lower lip with 2 barbels; gill membranes widely 

 joined to the isthmus, without distinct free fold posteriorly. Plates on 

 body with very strong spines, those of the dorsal series the largest, but 

 decreasing rapidly backward, becoming much smaller than the lateral 

 series under the second dorsal tin ; a median series of short sharp spines 

 still persists along entire back of tail after the confluence of the dorsal 

 series; the lateral series lower anteriorly, the upper row persisting to gill 

 opening, the lower row now becoming obsolete about 4 plates behind 

 axil; the abdominal series bear short sharp spines (longer in the young), 

 becoming obsolete along anterior portion of anal fin ; of the dorsal series, 

 4 are in front of the first dorsal, 10 (or 9i) along base of first dorsal, 1 (or 

 \\) between dorsals, 9 along base of second dorsal, 15 along back of tail, 

 the first of the latter being the plate in which the dorsal series first 

 becomes confluent; anterior portion of lateral line running along upper 

 lateral series, gradually descending to middle of sides where it runs on a 

 special row of plates which bear no spines; where the lateral line begins 

 to ascend, 3 of these become confluent with corresponding plates of the 

 upi^er lateral series ; in advance of these, .5 members of the series again 

 appear distiuct, considerably enlarged and bearing spines; 40 pores in the 

 lateral line; fins all comparatively short and low; pectorals reaching 

 twelfth iilate of Upper lateral series, the longest ray equaling length of 

 snout and \ eye; rays becoming rapidly shortened below, the lower 5 or 6 

 slightly thickened with exserted tips; veutrals very short, not exceeding 

 length of snout before mouth, not received into longitudinal groove. We 

 consider it verj^ doubtful whether such a groove exists in any of the other 

 species of this group. It has been described as existing in the types of 

 P. gilberti (Collett) and P. pcristethus, Gill. In both cases the type speci- 

 mens were in a poor state of preservation, and the groove was probably 

 due to a softening of that longitudinal strip of the abdominal wall, which 

 includes the anal opening, and extends backward from the base of the 

 ventral fins and is interposed between the firm outer series of ventral 

 plates. That such a softening had occurred in the type of Podoihecus 

 lyeristeilms is evident from Gill's statement that the ventrals had dropped 

 out. This view is rendered more probable from the lact that P.pc'riate- 

 thiis is apparently identical with the common P. acipenserinus which con- 

 tains no such groove. We have also examined 2 of the type of P. gilberti 

 without being able to satisfy ourselves of the existence of any special 

 groove. The dorsal fins are closely juxtaposed, the interspace including 1 

 or 1^ pairs of plates. The base of the last ray of second dorsal is midway 

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