182 
Fig. 7. Standard length/head-length ratio of Diplo- 
spinus multistriatus and Lepidopus gracilis. 
this size (Regan, 1916: fig. 7). The abdominal 
walls of Diplospinus are braced laterally by the 
very long, slender postcleithra. 
Attached to each pelvic bone is a hyper- 
trophied pelvic spine, V-shaped or nearly tri- 
radiate (through attenuation of the V’s apex) in 
cross-section, with about 20 spinules along each 
of its three edges. The two detached anal spines 
and the anterior four or five dorsal spines are 
similar to the pelvics in shape and armament, 
while the others are smooth and less obviously 
triradiate. The low number of soft dorsal rays 
(Table 3) is probably attributable to damage 
rather than youth, for a 10.4-mm specimen has 
10 more rays in this fin. 
The head is armed with a long slightly ser- 
rated spine at the preopercular angle, a shorter 
spine just above it, and two other short spines 
below, the last three spines being smooth. The 
three strengthening ribs of the upper opercle 
project from the opercular edge as slender 
spines. Dorsal to these projections are two spines 
at right angles to the body surface: a stout ser- 
rated spine on what is probably the pterotic, 
and a slender smooth one on the post-temporal. 
Two short spines occur above each eye. 
A pair of stout anterolaterally directed tusks 
lies at each side of the symphysis of the prog- 
nathous mandible, these being ventral to the 
jaw edge, horizontal in position, and unopposed 
by other teeth. Behind them are three or four 
retrorse denticles in the anterior half of each 
dentary, with no teeth posteriorly. The pre- 
maxillary has an enlarged tooth at either side 
of the symphysis, one or two retrorse denticles 
lateral to this, and six or seven tiny denticles 
PACIFIC SCIENCE, Vol. XVIII, April 1964 
scattered along the rest of its length. The vomer 
and palatines are ossified but edentulous. There 
is no trace of a cartilaginous jaw protuberance. 
Pigment is restricted to a brown spot distally 
in the membrane between the first three dorsal 
spines. 
At 13.2 mm (Fig. 9) the postlarva has be- 
come more elongate and less high-bodied. There 
is a variable increase in the number of dorsal 
and anal rays, and the spinigerous condition has 
spread posteriorly to include three-fourths of 
the dorsal spines. The caudal fin is beginning to 
fork. The preopercular spines are as before, 
while the post-temporal and pterotic spines are 
equal in size and both are smooth. The supra- 
orbital spines are short and inconspicuous. A 
peculiarity of this specimen is its possession of 
only two opercular-strengthening ribs, each with 
a spinelike projection. The normal number of 
ribs, and spines, is three. 
Just posterior to its nearly horizontal tusks 
each dentary bears an upright, unopposed tooth, 
and behind this is a row of eight emergent 
teeth extending to the rictus. The premaxillary 
has a pair of curved fangs on each side of the 
symphysis, followed by about six teeth of vary- 
ing size extending to the rictus. The vomer has 
two prominent teeth on each posterior tip, while 
the palatines lack teeth. A cartilaginous pad 
has not yet appeared at either jaw tip. The nasal 
capsule is visible as a yellowish sub-epidermal 
sac which lacks external ducts. 
TABLE 3 
COUNTS Made ON Diplospinus multistriatus 
STANDARD 
LENGTH 
(mm) 
DORSAL 
FIN 
ANAL 
FIN 
10.0 
XXX, 1, 16* 
II— 1, 19 
10.4 
XXX, I, 26 
II— I, 20 
11.1 
XXXI, I, 25 
II-1, 19 
11.2 
XXXII, I, 29 
II— I, 22 
12.0 
XXX, I, 27 
II— I, 23 
12.1 
XXXII, I, 27 
II— I, 20 
12.6 
XXX, I, 30 
II— I, 29 
13.2 
XXXI, I, 30 
II— 1, 23 
16.5 
XXXI, I, 33 
II— I, 27 
17.4 
XXXI, I, 35 
II— I, 28 
103 
XXX, I, 37 
11-1,31 
156 
XXXII, I, 35 
II— I, 28 
166 
XXXII-I, 38 
II— I, 30 
* Damaged ( ? ) . 
