58 SILtJRUS (PARASILURUS) ARISTOTELIS. 



of Comparative Zoology, collected by Dr. Roeser in the 

 Acheloiis (Aspro) river in Acarnania, Greece. The larg- 

 est is less than nine inches in length. From the young of 

 tS. glanis L., of equal length, they are readily distin- 

 guished by the possession of four barbels instead of six, 

 by the difference in shape of those on the maxillaries 

 they being shorter, less compressed and more threadlike, 

 by the wide separation in the middle of the band of vo- 

 merine teeth, by a larger eye, by a greater slope to the 

 sides of the head, by a smaller dorsal, by the smaller 

 number of rays in the anal, and by the markings. 



Young individuals of $. glanis, from the Danube, have 

 broader flatter heads, shorter lower jaws, smaller eyes, 

 longer flatter maxillary barbels, smaller pectoral spines 

 without denticulations in front and with very small ones 

 behind, blacker ventruls and pBctorals, and flanks marbled 

 with brown and white, the latter in irregular spots of va- 

 rying depth but distinct definition. The eyes have less of 

 a lateral outlook than in the Grecian species. 



Apparently the new species is a near approach to that 

 described as S. cliantrei, by Sauvage, from the Koura 

 (Kur) river, at Tiflis, a stream flowing into the Caspian. 

 The characters given that species are " D. 3; A. 65; P. 

 1 + 13; V. 10." "Allie au S. afghana, Gunther, en 

 differe par 1'epine pectorale non dentelee, la bande vomer- 

 ienne subinterrompueau milieu, les barbillons plus longs." 

 Giinther's type had maxillary barbels twice as long as the 

 head, vomerine teeth in a very narrow, uninterrupted 

 curved band, a pectoral spine without denticulations, a 

 dorsal with two rays and an anal with seventy. 



The specimens above described are undoubtedly those 

 of which Prof. L. Agassiz speaks in his communication 

 to the American Academy of Arts and Sciences, Nov. 12, 

 1856, published in volume in of its Proceedings, p. 325. 



