Alpheid Shrimp, X: Fiji, Tonga, Samoa— Banner and Banner 
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Fig. 8. Alp heus obesomanus Dana. 18 mm male from station BP 10. a, Anterior body region; b, second leg. 
Alpheus malleodigitus (Bate). 20 mm male from station BP 4. c, Anterior body region; d, second leg. Alpheus 
microstylus (Bate). 23 mm male from station BP 13. e, Anterior body region; f, second leg. 
second leg are presented in Figure 8. 
Orbital hoods and rostral front. As previously 
reported the anterior body region is variable; 
the rostrum itself in all three species is present, 
but may be exceedingly minute (de Man and 
Coutiere both reported specimens in which it 
was lacking ) ; and the frontal margin of the 
carapace between the orbital hoods varies from 
straight to bent inwards towards the rostrum. 
Antennular peduncles (Figs. 9 and 10). No 
sexual dimorphism was found in this charac- 
teristic; therefore figures for male and female 
were combined. The curves for the relative 
lengths of the first and second antennular ar- 
ticles show that while there is a statistical dif- 
ference between A. obesomanus and A. mal- 
leodigitus there is so much overlap that the 
characteristic cannot be used for species differ- 
entiation; A. microstylus also falls within the 
same range. The length-breadth ratio of the 
second article shows a greater contrast between 
A. obesomanus and A. microstylus on one hand 
and A. malleodigitus on the other, but again 
the difference is not clear-cut. It will be noted 
that in the wide variation in these characteristics 
