Hawaiian Crangonidae — Banner 
47 
carpus, with merus at least somewhat triangu- 
lar in section. Small chela of simple form, at 
times showing marked sexual dimorphism. 
Carpus of second legs of five articles of 
variable proportions. 
Third and following legs robust, com- 
pressed; armature and proportions of merus, 
carpus, and propodus various, dactylus sim- 
ple or biunguiculate. Fifth legs with "brush” 
on propodus. 
Abdomen usually without lateral compres- 
sion, with pleura in females larger than those 
of males and usually without acute projections 
on margins. Pleura of sixth abdominal seg- 
ment not jointed. Telson usually with pos- 
terior margin convex and lateral angles dis- 
tinct but not acute. Anal tubercles well de- 
veloped. 
Branchial formula: 5 pleurobranchs, 1 ar- 
throbranch, 8 epipodites, and sometimes a 
supplementary arthrobranch on first thoracic 
legs (except in C. paragracilis Coutiere and C. 
nanus Banner) . 
This genus, previously known to American 
systematists and still known to European sys- 
tematists as Alpheus, is by far the largest in the 
family, not only in Hawaiian waters, but also 
in the entire Pacific. In 1911 de Man listed 
128 species of Crangon in comparison with 62 
species of Synalpheus, the next largest genus. 
In this paper 31 species from Hawaii are dis- 
cussed; in addition there are two species re- 
ported from Hawaii, the records of which are 
doubtful. 
To facilitate the classification of the genus, 
Coutiere (1899) divided it into five groups, 
principally on the basis of evolutionary devel- 
opment of the large chela and to a lesser 
extent on other characters, such as the charac- 
ter of the frontal margins of the carapace, the 
character of the dactylus of the third legs, etc. 
Later he divided the third group, Crinitus, into 
three subgroups (1905). These groups as orig- 
inally defined were sharply distinguished one 
from another and constituted a valuable aid 
to the separation of the species. 
Many new species were described after the 
groups were defined, for example, Coutiere 
(1905) described 23 new species from the 
Maldives and Laccadives, and de Man (1911) 
described some 20 new species from the col- 
lections of the Siboga Expedition. Since these 
did not exactly conform to the original de- 
scriptions of the groups and subgroups, mod- 
ifications of the definitions were made. 
On the basis of the Hawaiian species it ap- 
pears that these groups, unlike those of Syn- 
alpheus, probably are still quite valid in deter- 
mining the relationships of the species. How- 
ever, should some future worker have avail- 
able to him a collection of a large number of 
species, these groups should certainly be re- 
evaluated and some of the species be assigned 
either to others of the present groups or to 
new groups; by doing this some of the am- 
biguity of the definitions of the groups could 
be avoided. If that were done it would be de- 
sirable to raise the groups to subgenera. 
While the groups in general show close re- 
lationships of the species within them, the 
utility of the groups as redefined by de Man 
is definitely questionable. Some species could 
fall into two or three groups, as defined, with 
equal ease, as the revised definitions often are 
equivocal and ambiguous. For example, de 
Man’s definition of the Macrochirus Group 
(191 1: 307; italics mine): 
Lateral (extracorneal) spines usually present. Inferior 
spine of basicerite sometimes large. Larger chela usually 
longitudinally grooved or emarginate anteriorly. Merus 
of third legs usually unarmed, dactyli of three posterior 
legs biunguiculate or simple. External spine of exopod of 
caudal fan often black. 
Because the groups do seem to follow the 
natural relationships, they have been used in 
this paper. However, because the definitions 
of the groups are not clear and definitive, it 
has been impossible for the major divisions 
of the key to the species to follow the group- 
ings. Instead, the key keeps all members of 
one group in a single series and in the se- 
quence in which they are discussed in the 
text. For ready reference the Hawaiian species 
are listed here by groups. 
