412 SMITHSONIAN MISCELLANEOUS COLLECTIONS [voL. 48 
In specimens of both guttatus and y-grecum two and one-fourth to 
three inches long, the skin is scaleless, and the head above has an 
osseous casque extending close up to the nostrils and between the 
eyes. This was supposed to be characteristic of Astroscopus and 
that genus was originally based on such characters. As the fishes 
increase in size the slight naked space behind the nostrils becomes 
enlarged and the enlargement continues until the large naked areas 
characteristic of the adult Upsilonophorus are developed. The 
identity of the two genera was recognized by Gill as early as 1872, 
but the differences seemed to be so great that some elapsed before 
the identification was entirely accepted. 
Ill 
A third well-marked genus (Kathetostoma) is represented by a 
couple of species in warm American waters. 
Fic. 119.—Kathetostoma albigutta. After Jordan and Evermann. 
The Cathetostomes (Kathetostoma) have the 
branchial apertures limited above by membranes 
partly bridging the interspace between the oper- 
cles and shoulders; the skull above is completely 
ossified, the preopercles are armed with three or 
four acute plectroid spines directed downwards, 
as in the Uranoscopes, but there is no suboper- 
cular spine; there are a pair of free and acute 
spines, one to each shoulder, and a pair of acute 
spines pointed forwards on the pelvic bones; the 
nostrils are very small, the anterior subtubular, 
the posterior a pore-like opening ; scales are want- 
ing ; the soft dorsal fin alone is developed ; there is 
Fic. 120.—Kathe- 
tostoma  albigutta. 
After Jordan and : : j 
Evermann. no intralabial filament. Two species of the genus 
are known as Americans, one (K. albigutia) 
from the Gulf of Mexico, and another (K. averruncus) from the 
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