58 SILURUS (PARASILURUS) ARISTOTELIS. 
of Comparative Zoology, collected by Dr. Roescr in the 
Acheloiis (Aspro) river in Acarnania, Greece. The lari;- 
est is less than nine inches in length. From the young of 
S. 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, 
])y 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 S. glanis, from the Danube, have 
broader flatter heads, shorter lower jaws, smaller eyes, 
longer flatter maxillary barbels, smaller pectoral spines — 
without denliculations in front and with very small ones 
behind, blacker ventrals and pectorals, 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 8. cJiantrei, hy Sauvage, from the Koura 
(Kur) river, at Tiflis, a stream flowing into the Caspian. 
The characters given that species are " D. 3 ; A. 05 ; P. 
1 4- 13; V. 10." "Allie an .S'. afghana, Gimther, en 
diftere par I'epine pectorale non dentelee, la bande vomcr- 
ienne subinterrompue au milieu, les barbi lions plus longs." 
Gunther's type had maxillary barbels twice as long as the 
head, vomerine teeth in a very narrow, uninterru})ted 
curved band, a pectoral spine without denticulations, a 
dorsal with two rays and an anal with seventy. 
The specimens above described are undoubtedl}' those 
of which Prof. L. Agassiz speaks in his connnunication 
to the American Academy of Arts and Sciences, Nov. 12, 
185G, pnblished in volnme in (>^" its Proceedings, p. 325. 
