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PACIFIC SCIENCE, VoL VII, January, 1953 
form and gradual. Furthermore, although in 
most large specimens the tip of the rostrum 
was depressed as shown in Figure 43^, in a 
few of intermediate size it was found to con- 
tinue almost ' ’level,” and in one it was slight- 
ly elevated. 
A second field of variation was in the carpal 
articles of the second legs; some had the ratio 
given above, but in some the ratio of the first 
two articles approached 10 : 13. None were 
noted where the second article was shorter 
than the first. 
The third variation was in the propodus of 
the third legs. 'Small specimens had only four, 
five, or six spines well developed; among the 
large specimens some had a few more, some 
had a few less, than the 20 described. 
Since the original description of this spe- 
cies from the Hawaiian Islands by Dana, no 
specimens have been reported. In 1861 Heller 
described from the Red Sea what was appar- 
ently a closely related form, Alpheus insignis, 
and all later workers, evidently because they 
were not certain of the characteristics of 
Dana’s species, used Heller’s name. As C. in- 
signis the species was later reported from the 
Hawaiian Islands. Coutiere in 1899 (p. 500) 
listed C. insignis as a synonym of C. diadema 
but in 1909 (p. 899) reviewed the situation 
and decided, like de Man, to reserve judg- 
ment until Dana’s type was redescribed. Un- 
fortunately, the type of Dana’s species was 
lost, and it was impossible to determine the 
exact characteristics of the species. 
To resolve this uncertainty, a special trip 
was made to Lahaina, Maui, the type locality, 
to collect replacement type specimens for 
Dana’s description. This effort was successful 
as the reef at Lahaina had a larger proportion 
of this species than any other locality visited, 
and the specimens also were larger and more 
robust. One of them is described above. 
This neotype differs in five minor ways 
from Dana’s drawings and description. First, 
the margins of the base of the rostrum were 
shown as definitely and uniformly concave 
throughout their length between the orbital 
hoods, instead of straight and parallel as they 
are in this specimen; however, as noted above, 
this is a variable character. Second, his profile 
drawing shows the rostrum as turning up near 
its apex, instead of being depressed as in this 
specimen; this, too, is a variable characteristic. 
Third, the margin between the base of the ros- 
trum and the anterior orbital hoods is shown 
as concave instead of convex; this may be due 
to faulty delineation in the drawing. Fourth, 
the second carpal article of the second legs 
was described as being much shorter than the 
first and was shown to have the ratio (approxi- 
mately) of 10 : 7 instead of 10 : 10 or 10 : 12, 
as found in all the specimens in the collection. 
Finally, the propodus was described as bear- 
ing "six sets of spinules on inner side,” in- 
stead of approximately 20 found in the neo- 
type. This last difference could be attributed 
either to the immaturity of Dana’s specimens 
or to inadequate observation. 
Thus, the only significant difference be- 
tween Dana’s description and this neotype is 
in the ratio of the carpal articles of the second 
legs. This may be due to a chance variation in 
the specimens or to faulty observation; but, 
even if an actual difference, it would not be a 
sufficient difference to warrant calling the lo- 
cal specimens other than diadema. 
I can find no significant differences between 
this species and the form described by Heller. 
Heller shows the margin between the rostrum 
and the anterior margin of the orbital hoods 
to be concave instead of convex (as did Dana) 
and somewhat more narrow; he describes the 
propodus of the third legs as bearing seven or 
eight spines. As these differences, if correct, 
would be at most of only subspecific value, 
Heller’s species is placed in synonymy. 
Table 5 contrasts this with related Hawaiian 
species. 
distribution: This species is common in 
the shallow waters of the Hawaiian Islands. 
On the reef flats or in water to 20 feet deep it 
has been collected from the following locali- 
ties: on Oahu, Kaneohe Bay, Mokulua Is- 
land, Waimanalo, the shore near Koko Head, 
