PLECTRITES 29 



long and strong interneurals. Second dorsal with interneurals short 

 and weak. Ventrals well developed, with a strong spine, inserted well 

 behind pectorals, but attached to a very strong and long pelvic bone. 

 Pectorals moderate. Head obliterated. 



Five more specimens, since examined, are without antrorse dorsal 

 spine, the sole character by which PLECTRITES can be separated from 

 RHYTHMIAS. But in no case are we sure that it was actually absent. 



Plectrites Jordan, new genus. 

 (Type: PLECTRITES CLASSENI Jordan). 



Spariform fishes with a sharp horizontal spur directed forward, at 

 the base of the first dorsal spine. Body elliptical, compressed, rather 

 deep. Head not preserved, the depth of body about 3 l / 2 in length to base 

 of caudal. Vertebrae about 30, deeper than long, slightly grooved, neural 

 strong; interneurals straight, not expanded at base, those in front well 

 separated, two or three for each pair of neurals ; those under soft dorsal 

 short, close-set, parallel, two or three for each pair of neurals ; interhsemals 

 all short and weak. 



Dorsal continuous, scarcely notched; the rays low, D. XII, I, 11. 

 Anal opposite soft dorsal. Other fins lost. 



13. Plectrites classeni Jordan, new species. 

 (Plate XVIII) 



Type No. 313, part of side of fish, 8 l / 2 inches long. Body regularly 

 elliptical, compressed, deepest mesially. Depth about 3y 2 ; head lost, ver- 

 tebras about 25, deeper than long, slightly grooved ; neurals rather strong, 

 interneurals straight, not expanded at base, those in front well separated, 

 those under second dorsal close together, short and parallel. 



Dorsal with a sharp antrorse spine at base of first spine and almost 

 as long. It is attached at the base of the first spine and to the same inter- 

 neural. Dorsal spines thirteen. The first spine *4 length of fourth, the 

 rest shortened behind, connected closely with second dorsal, which is low, 

 even, with slender rays. D. XII, I, 11. 



Anal opposite soft dorsal, its interhsemals all short and weak ; ven- 

 trals and pectorals lost ; a few moderate scales. This fish has the dorsal 

 fin and its antrorse spine much as in the SPAROID genera, STENOTOMUS 

 (STENESTHES) and LAGODON. The presence of this spine with a rather 

 more elongate body alone separates this genus from RHYTHMIAS. The 

 antrorse dorsal spine is found also in AMBASSIS, SCATOPHAGUS, ACAN- 

 THURUS and SIGANUS, but the present genus is evidently sparoid. 



The species is named for its discoverer, Mr. WILLARD J. CLASSEN of 

 Stanford University. 



