36 THE AMERICAN NATURALIST. (VoL. XXXV. 
many daysafterhatching. It is not probable that they migrated 
into the cave as separate individuals, unless they came from a 
source as limited in extent as the cave itself. Specimens 
migrating from a more extensive source would, under no prob- 
ability, show the similarity of variation to be here recorded. 
In common with all the other North American fresh-water 
catfishes, Ameiurus melas is provided with a barbel in front of 
each posterior nasal opening. In the specimens under consid- 
eration there are usually one or more additional barbels behind 
the first, frequently on the anterior lip of the nasal opening. 
These barbels in detail are as follows, all measurements being 
in millimeters ! : 
B | LENGTH OF THE LEFT NASAL LENGTH OF THE RIGHT NASAL 
ee 2 | BARBELS AND THE SUP- BARBELS AND THE SUP- 
Pas s PLEMENTAL ONES. PLEMENTAL ONES. 
1 Le l* €, 4. 16, 1 (Fig.2 A) 
2 86. | £—t*, 18 11, 7.9 (Fig. 2 B) 
I 
3 78 11: 11,2 
4 78 ILG 11,4 (Fig.2C) 
5 78 11 and small lobe 6, 10, 2 
5 d WE 
6 76 11, Hoy 11 
7 74 | minute, 11, 3 minute, 11, 14 
8 74 10, minute 10, lobe on narial lip 
9 78 2g x 10, : 
à On the left side there are two supplemental barbels. 
edge of the main barbel is 6 mm. long. One behind the outer edge is T-shaped. 
segment is but 1 mm. long. The upper segment slants from behind 
The 
One behind the inner 
upward and gig Behind the basal segment it is 2 mm. long, the portion 
in front 4 m 
b puden ar on d edge of the narial lip. 
c The supplemental barbel is Y-shaped, with the basal m L pum. deb 
the distal segments each 4 mm., and placed on the edge of the i 
d Here there are two lobes on the narial margin, but no distinct development 
of PCs 
Y-shaped, with a basal segment 1 mm. long, and distal segments respectively 
x uud 2 mm. 
n the columns of lengths the figures representing the lengths of the various 
d barbels ar 
are placed in the same relation to the sevi of the main 
barbel as the supplemental barbels are placed to the principal barbel. 
