Pacific Alpheids II — Banner 
201 
pace is different, (compare Fig. 5 a to de Man, 
1911, pi. 15, fig. 74), the flattened portion 
of the scaphocerite is longer and more narrow, 
the second carpal article is only 1.3 instead of 
2.1 times as long as the first, the telson is 
more tapering and the spines and spinules of 
the uropods and telson were unreported by 
de Man. 
The specific name refers to the type locality. 
Alpheus bucephalus Coutiere 
Alpheus bucephalus Coutiere, Fauna and Geog. 
Maidive and Laccadive Archipelagoes 
2(4): 890, pi. 78, fig. 29, 1905. 
Alpheus consobrinus de Man, Leyden Rijks 
Mus. van Naturlijke Hist. Zool. Meded., 
Notes 30:101, 1908. 
Alpheus consobrinus de Man, Siboga Exped. 
39a 1 : 360, pi. 16, fig. 75, 1911. 
LOCALITIES: One specimen at E-l-122; 11 
at E-l-306; 4 at E-2-360. 
discussion: A. consobrinus was recognized 
by de Man as being closely related to A. 
bucephalus and A. clypeatus Coutiere, but was 
separated by him on the basis of the following 
characteristics: 
1. The scaphocerite is slightly longer than 
the carpocerite in A. consobrinus and slightly 
shorter in A. bucephalus. 
2. The basicerite is armed with a minute 
tooth in A. consobrinus and unarmed in A. 
bucephalus. 
3. The merus of the large chela bears an 
acute tooth on the inferior internal margin in 
A. consobrinus while in A. bucephalus the cor- 
responding projection is rounded. 
4. The small chela is usually dimorphic in 
A. consobrinus , the males bearing an expanded 
dactylus with a fringe of setae, while in A. 
bucephalus the dactylus of the small chela of 
the male is narrow, conical and without a 
fringe of setae, a condition similar to that of 
the females. 
5. The second article of the second leg is 
three times the length of the first in the males 
of A. consobrinus while in both sexes of A. 
bucephalus (according to de Man’s key) it is 
"more than twice as long as the first.’’ (How- 
ever, Coutiere’s figure 29c shows it to be 
about 2.75 times as long as the first.) 
6. The telson is slightly more narrow in A. 
consobrinus , the length-breadth ratio being 2.6, 
while in A. bucephalus where the ratio is 2.2. 
This impressive list of differences would 
lead one to believe that the species are sep- 
arate and distinct. However as previously re- 
ported from Saipan, the broadening of the 
dactylus of the males is not a constant char- 
acteristic. In this series of specimens a group 
collected at E-l-306 shows that each one of 
these characteristics is individually variable. 
In Table 1 a tabulation of these characteristics 
of 10 intact specimens is given. The relative 
lengths of the scaphocerite and carpocerite 
are quite variable; the spine of the basicerite 
is present in only two specimens; the meral 
spine of the large chela varies from strong 
and acute to low and rounded; the dimorphic 
character of the small chela of the males does 
not seem to be correlated with size or other 
characteristics; the ratio of the first two sec- 
ondary articles of the second leg varies from 
1.7, a figure below that of A. bucephalus , to 
3.5, a figure above that of A. consobrinus; and, 
finally, the telsal length-breadth ratio ranges 
from 2.1 to 2.9, the last in the smallest speci- 
men. Moreover, the variations are not cor- 
related with each other, so a specimen like 
A. consobrinus in the sexually dimorphic chela 
does not have the tooth on the basicerite, etc. 
These variations parallel or exceed the varia- 
tions previously reported upon for the closely 
related A. clypeatus Coutiere and A. brevipes 
Stimpson (Banner, 1953: 103-110). I believe 
that when sufficient specimens are examined 
from all parts of the range of these four 
nominal species, it is very likely that the 
species will all be found to be part of a single, 
very variable species. However, the present 
series of specimens do not offer enough direct 
evidence to warrant this lumping except to 
combine A. consobrinus with A. bucephalus. 
