478  .BULLETIN 100, UNITED STATES NATIONAL MUSEUM. 
with a free fold. The center of the anus is in advance of its normal 
position before the origin of the anal fin, the interspace being con- 
tained 1.4 (1.0 to 2.0) times in the distance between the anus and the 
base of the outer ventral ray; the latter distance is contained 1.4 
(1.83 to 2.0) times in the interval between the ventral fin and the isth- 
mus, or 1.4 (1.3 to 1.8) times in the postorbital length of the head. 
Summarized table of proportion of parts of the head.’ 
| 
ie Sot Hoe | Type- 
Variation. specimen. 
| . 
Orbitiin headers. . Saas see eee oe OE ae ee ee ee ee ae 3.05 to 3.3 3. 05 
Onbit. in’ postorbiltall: ssc oe se oan aces eee oon Set nee eee gee eee 0.8 to 1.0 0.8 
Orbit in snout......... Sede dais Sais as Se Ree See eat nea cae eae Eee eos 1.2 to 1.4 1, 25 
interorbital in -postocbitalvess2 555. 25 tae Roa a See eee eee 1:3 to 1.5 1.5 
Suborbitaliinipostorbivalc == sass os eee edee nae at SNELL IA SS 2 oe eens 2.0 to 2.25 2.0 
Upperiiaw in headee ess. se eee eer eee eee ate 4.1 to 4.65 4.2 
Barbelin postorbitale..2.72 Se sania eee eee ce oe ee oe ee eee ne eee 3.6 to 5.5 5.0 
Length of snout in head: 
PreOCWlAl 22's; se sccences seme dese sesso oe ee cee ares BE ee ea anise res eed 2.25 to 2.6 2.5 
Preoral 5.2. x oSteasts cma Peete ae ase eee ee ee SR eee ee es 2.4 to 2.9 2.9 
Width offsnoutiinthead..<-2.cc.k+ 5. het ce PA es eke! Se 2.4 to 27 2. 55 
Width of snout at end of ethmoid region of infraorbital ridge, measured 
into lengthvof: snout beforethat pomt:: Wo. 2es-.ce- eon anes e eee ee eee 0.8 to 1.0 0. 85 
1 Measured in each case on 22 specimens, varying in length of head from 30 to 47.5 mm. (excepting case of 
barbel, measured in 16 specimens). Length of head in type-specimen, 44 mm. 
The scales, especially those on the head, are loosely imbricate; 
they are larger than in any other species of the notatus group, there 
being constantly but 4 or 43 in a series from the origin of the second 
dorsal to but excluding the scales of the lateral line. The scales of 
the body are about as rough as in argus or velifer, but those on the 
head, especially along the ridges, bear longer and stronger spinules. 
On each scale of the body there are from 9 to 11 parallel rows of 
slender and usually long spinules, the arrangement of which is 
slightly irregular as a result of the obsolescent character of the 
ridges along which the spinules are usually borne. The last spinule 
of each series often projects well beyond the margin of the scale. 
Six to 8 scales, studded with strong conic spinules, bound the eth- 
moid region of the infraorbital ridge; there are 8 to 11 scales on the 
preorbital section of the ridge. There are 8 (6 to 9) scales in a series 
along the superior rostral ridge; from near the anterior margin of 
each of these elongate scales there radiate backward several series 
of fine spinules. This median rostral series is bounded on each side 
by a single series of rather large scales bearing spinules in several 
series directed chiefly backward and inward, but not differentiated 
into two groups as usual in related species. The squamation of the 
region between the occipital ridges offers diagnostic characters: 
along the region vertically above the orbit there are three very regu- 
lar and parallel rows of scales similar to those of the body (in 
paratypes smaller scales are sometimes interpolated between these 
series, rendering the arrangement less regular) ; between the abrupt 
