SAND-LAUNCE. 
575 
Ainmodytes lancea , Cuv., Regne Anim., ed. 2, tom. II, p. 300; 
Nilss., Proclr. Ichthyal. Scand ., p. 03; Kb., 1. c., p. 593; 
Nilss., Skaiul. Fn., Fisk., p. 650; Malmgr., 1. c.; Lindstr.. 
Goil. L. Hush. Sallsk. Arsber. 1860, p. 24 (sep.); Mela, 
Vert. Fenn., p. 296, tab. IX; Lillj., I. c., p. 221. 
The Sand-Launce never attains so great a size as the 
maximum size of the Sand-Eel. K royer’s largest spe- 
cimen was 187 mm. long; a specimen from Greenland, 
brought home by O. Torell, measures 204 mm. from 
the tip of the lower jaw to the end of the longest rays 
of the caudal tin, or 197 mm. from the tip of the snout 
to the end of the middle rays of the same fin. 
The body is generally somewhat deeper and more 
compressed than that of the Sand-Eel, though no constant 
character can be drawn from this relation. The greatest 
depth of the body, across the belly, varies in ordinary 
cases between about 9 and 10 V 8 % of the length from 
the tip of the lower jaw to the end of the outer rays 
of the caudal tin, and the greatest breadth between 
about 66 and 75 % of the greatest depth. We have 
found the depth at the beginning of the anal fin to vary 
between 6 1 / 5 and 9 vi % a of the length of the body 
from the tip of the snout to the end of the middle 
caudal rays; and, in the same specimens, the greatest 
breadth varied between 4 and 77 3 % h of the same length. 
In specimens of equal size the head is of essen- 
tially the same shape as in the Sand-Eel; but as a rule 
it is shorter. In specimens between 95 and 197 mm. 
long we have found its length to vary between 19 and 
17 3 / 4 % of that of the body. The longitudinal diameter 
of the eye varied in these specimens between 20 and 
13 % of the length of the head. The length of the 
snout varied between 64 and 56 % of the postorbital 
length of the head or between 33 and 30 % of the total 
length thereof. The least breadth of the interorbital 
space varied between 2V 3 and 3 2 / 5 % of the length of 
the body or between 12 1 / 2 and 197 2 % of the length 
of the head. 
In the nostrils we find scarcely any difference from 
those of the Sand-Eel; but the structure of the mouth, 
as we have remarked above, affords one of the most 
important characters for the Sand-Launce and the forms 
akin to it in this respect. The mobility of the inter- 
maxillary bones is produced in the same manner as in 
the case of most other fishes, and in striking contrast 
to the Sand-Eel. The difference lies partly in the long 
a In the Sand-Eel between 6 2 / 3 and 8 %. 
b al, o/ 
1111 ii ii ° 13 ii ° 13 /”• 
c ,, ,, ,, from 16’3 % to 15'3 %. 
nasal processes, which glide forward and backward in a 
groove in the upper surface of the ethmoid bone, partly 
in the greater length of the muscular band that extends 
under each of these processes, starting from the inner 
(posterior) surface of the front of the intermaxillary 
bone and from its articular process (cf. the explanation 
of fig. 118, p. 463, above), and attached to the inward 
vomeral process of the maxillary bone, which process is 
closely united by ligaments to the anterior end of the 
vomer. These two muscular bands serve to draw back 
the intermaxillary bones. The protrusion of the inter- 
maxillary bones is effected by their union to the lower 
jaw by skin, muscles, and ligaments, and they thus 
follow the lower jaw when it is depressed. The anterior 
end of the maxillary bones is rendered independent of 
this downward motion by the union of the vomeral 
processes to the vomer; and on casual examination these 
processes, with their sharp, transverse, osseous points, 
present a confusing resemblance to the teeth on the 
head of the vomer in the Sand-Eel — they have several 
times been confounded with those teeth. The length of 
the upper jaw shows even relative increase with age 
from the earliest stages until the fish is of middle size, 
but it subsequently seems to be retrogressive, unless 
our observations are based on individual variations. In 
a specimen 30 mm. long we find this length to be 2 2 2 / 3 
% of that of the head, and in larger specimens, up to 
a length of about 13 cm., this percentage increases to 
about 33; but in our largest specimen the proportion 
is no more than 28 V 2 %. The lower jaw is usually 
shorter than in the Sand-Eel, its length being about 
8 % (between 8'6 — exceptionally 9'3 — and 7‘6 %) of 
that of the body, or about 45 % (between 47'8 — in our 
smallest specimen 49 — and 42*8 %) of the length of 
the head, and never so much as 15 % ( 14*2 C — 12*2 %) 
of the length of the base of the dorsal fin. The conical 
tip in which the lower jaw projects beyond the tip of 
the snout, is also generally less than in the Sand-Eel, 
and seems at most not to exceed V 4 of the length of the 
snout proper. The gill-rakers are setiform in this species 
too, and number 22 or 23 on the first branchial arch. 
The lips, tongue, palatal folds, pharyngeal bones, and 
gill-covers resemble those of the Sand-Eel, but the oper- 
culum is more scalene, with the lower side (along the 
suboperculum) perceptibly greater than the upper. The 
Scandinavian Fishes. 
73 
