504 
BULLETIN OF THE UNITED STATES FISH COMMISSION. 
Genus 145. DACTYLOSCOPUS Gill. 
Body moderate' y elongate, covered with rather large, cycloid scales; head cuboid, oblong, and 
nearly flat above; eyes small; interorbital space broad; mouth nearly vertical; lower jaw not dilated 
beneath nor emarginate in front, without barbels; no intralabial filament; teeth villiform, on jaws 
only; pseudobranchise very small or obsolete. Dorsal commencing at nape, with 6 to 12 slender 
spines, soft rays numerous; anal inserted behind dorsal; ventral rays, i, 3. 
a. Dorsal rays x to xn, 22 to 31; anal rays fewer than 35. 
b. Soft dorsal with 28 to 31 soft rays; anal with 32 or 33; scales about 45. 
c. Body rather slender, depth about 6 in length (7 with caudal); opercular fringe of 15 filaments tridigitatus, 257 
cc. Body rather stout; depth 5.25 in length (6 in total with caudal); opercular fringe of 18 filaments. 
d. Back not barred; head blotched and dotted poeyi 
257. Dactyloscopus tridigitatus Gill. 
Head 5 (in total) with caudal; depth 7; D. xii, 28; A. ii, 32; P. 13;V. i, 3; scales 11 -(-4 + 30 = 45. 
Body slender, much compressed posteriorly; opercular fringe of 15 separate filaments. Origin of dorsal 
fin over lower angle of base of pectorals, or immediately before margin of operculum, its distance from 
snout to dorsal 5 in total length of body. Pseudobranchise very small (overlooked by Dr. Gill, but 
evident in living specimens). 
In life, pale sand-color above, lower part whitish ; above 12 narrow crossbands of whitish on the 
back, not extending down far on the side; head mottled above; fins all pale. 
This species of star-gazer is found in the West Indies and the Barbados and north to southern 
Florida. It has been taken at Key West and Cape Florida, and a single example, 3 inches long, was 
seined by us in Ensenada del Boqueron, Porto Rico. It does not reach a length of more than a few 
inches, and is a shallow-water fish, frequenting the coral sands near shore, in which it is wont to bury 
itself, leaving only its eyes and mouth exposed, after the fashion of the flounders. 
Dactyloscopus tridigitatus Gil), Proc. Ac. Nat. Sci. Phila. 1859, 132, Barbados; Jordan & Evermann, 1. c., 2301, 1898., 
Family LXX. GOBIESOCIDtE. Cling-fishes. 
Body rather elongate, tadpole-shaped, broad and depressed in front, covered by smooth, naked 
skin; mouth moderate; upper jaw protractile; teeth usually rather strong, anterior conical or incisor- 
like; posterior canines sometimes present; suborbital ring wanting; no bony stay from suborbital 
across the cheek; operele reduced to a spine-like projection concealed in skin, behind angle of large 
preopercle, this spine sometimes obsolete; pseudobranchise small or wanting, the gills 3 or 2.5; gill- 
membranes broadly united, free or united to isthmus; dorsal fin on posterior part of body, opposite to 
anal and similar to it, both fins without spines; ventral fins wide apart, each with 1 concealed spine 
and 4 or 5 soft rays. Between and behind ventrals is a large sucking-disk, the ventrals usually forming 
part of it. This sucking-disk, which is wholly different in structure from that of Cyclopterus and 
Liparis, is thus described by Dr. Gunther: 
“The whole disk is exceedingly large, subcircular, longer than broad, its length being (often) 
one-third of the whole length of the fish. The central portion is formed merely by skin, which is 
separated from the pelvic or pubic bones by several layers of muscles. The peripheric portion is 
divided into an anterior and posterior part by a deep notch behind the ventrals. The anterior 
peripheric portion is formed by the ventral rays, the membrane between them, and a broad fringe 
which extends anteriorly from one ventral to the other. This fringe is a fold of the skin containing on 
one side the rudimentary ventral spine, but no cartilage. The posterior peripheric portion is suspended 
on each side on the coracoid, the upper bone of which is exceedingly broad, becoming a free, movable 
plate behind the pectoral. The lower bone of the coracoid is of triangular form, and supports a very 
broad fold of the skin, extending from one side to the other and containing a cartilage which runs through 
the whole of that fold. Fine processes of the cartilage are continued into the soft striated margin, in 
which the disk terminates posteriorly. The face of the disk is coated with a thick epidermis, like the 
sole of the foot in higher animals. The epidermis is divided into many polygonal plates. There are 
no such plates between the roots of the ventral fins.” (Gunther, Cat., in, 495.) 
No air-bladder; intestines short; pyloric caeca few or none; skeleton firm; vertebrae 13 to 14 + 13 
to 22 = 26 to 36. 
