Hawaiian Crangonidae — BANNER 
93 
be displaced, exposing the eyes as is shown in 
Figure Five specimens of this species 
show this condition to some degree. The pos- 
sible causes of the condition are discussed 
under C. paragracilis. 
Normally occurring variations were slight. 
In one specimen the orbital hoods are equal 
to the rostrum in length. Slight differences in 
the proportions of the carpal articles of the 
second legs and in the proportions of the ar- 
ticles of the third legs were observed but all 
articles, exhibited a generally consistent if not 
exact relationship one to another. Finally, the 
articles of the antennal peduncle between the 
basicerite and the carpocerite are or are not 
visible in lateral view, the differences evident- 
ly caused by the degree of rotation of the car- 
pocerite. 
relationship: Because of the close rela- 
tionship this species bears to C. paragracilis 
(Coutiere) it has been placed in the Macro- 
chirus Group. According to de Man’s key 
( 1911 ) this species is a relative of C. macro- 
chirus (Richters) . However, it does not appear 
to be closely related when the characteristics 
of the latter species are considered, for macro- 
chirus has deep orbitorostral grooves, the sec- 
ond antennular article is three times the length 
of the third antennular article, and the fingers 
of the large chelae are proportionally larger. 
Certainly, of all Hawaiian species this spe- 
cies is most closely related to C. paragracilis 
(Coutiere) and to the close relative of C. para- 
gracilis, C. hawaiiensis Edmondson. As C. ha- 
waiiensis is distinguished from C. paragracilis 
principally in the form of the large chela, as 
C. paragracilis is better known, and as C. para- 
gracilis is probably the parent species to both 
this species and C. hawaiiensis, C nanus is com- 
pared chiefly to C, paragracilis. In the two spe- 
cies the form of the anterior carapace is almost 
exactly the same; the compact antennular pe- 
duncle and the styloceiite are similar; the long 
and heavy carpocerite is similar; the peculiar 
mouthparts are similar; the general shape of 
both the large and small chela are similar 
(specific differences are noted below) ; the re- 
lationship of the lengths of the carpal articles 
of the second legs are roughly the same; even 
the curvature of the propodus is similar in 
both species. The branchial formula is similar 
and evidently different from all other mem- 
bers of this genus. 
In fact, there is sufficient similarity between 
the two species so that they could easily be 
confused unless they were closely examined. 
The chief differences lie in the following char- 
acteristics: the large cheliped, in which the 
chela has the inferior margin entire and the 
merus unarmed in C. nanus, but with the chela 
bearing a shoulder on its inferior margin and 
the merus with spines on the inferior internal 
margin and a spine on the superior distal 
angle in C. paragracilis; the pleopods, which 
are of the usual form in C. paragracilis and as 
shown in Figure 31 in C. nanus; the merus of 
the third leg which is unarmed in C nanus 
and bears an acute tooth in C paragracilis. 
Furthermore, in C. nanus the scaphocerite is 
shorter than the antennular peduncle, the me- 
rus of the second leg is equal in length to the 
first four carpal articles, and the inferior un- 
guis of the dactylus of the third leg is normal- 
ly about 0.75 as long as the distal unguis, 
whereas in C. paragracilis the scaphocerite is 
longer than the antennular peduncle, the me- 
rus of the second leg is equal in length to the 
first three carpal articles, and the inferior 
unguis of the third legs is 0.25-0.3 the length 
of the distal claw. The differences between 
the two species appear to be constant. 
There is one other description in the litera- 
ture that appears to be of the same or a closely 
related species, that of " Alpheus sp.? Metal- 
pheus n. gen.?" of Coutiere {loc. cit.). There 
seems to be some confusion about this spe- 
cies, for while Coutiere states it shows rela- 
tionship to C. paragracilis and considers it as 
possibly identical to the unfigured C. rostra- 
tipes (Pocock, 1890), he also considers it as a 
representative of a new genus. 
C nanus is similar to " Alpheus sp." in many 
important respects: the form of the orbital 
hoods, anterior carapace, antennules and an- 
