14 PROCEEDINGS OF THE NATIONAL MUSEUM VOL. 120 
regarded as ‘‘vestigial’’ (see p. 6; also Schmitt, 1940, fig. 18b). 
These were only observed in three specimens of H. ensigera. 
L/B rostrum: 1.1088, cf. 1.1021 for nearest H. ensigera value 
(Australasian), difference not significant (p 0.8). 
L carapace/L rostrum: 3.9650, cf. 4.0543 for nearest and lowest 
H. ensigera value (Californian), difference not significant (p 0.4-0.3). 
L/B cornea: 1.0556, cf. 1.2013 for nearest and lowest H. ensigera 
value (Australasian), difference just not significant (p 0.2—0.1). 
L eye/B cornea: 1.1544, cf. 1.3220 for nearest and lowest H. 
ensigera value (Australasian), difference highly significant (p <0.001). 
Summarizing these differences, H. braziliensis differs from H. 
ensigera in having (1) in all cases, more spinous telson teeth and 
(probably) differently shaped basal processes of uropods; and (2) 
statistically significant differences as follows: a larger number of seg- 
ments in the mandibular palp, a higher proportion of individuals with 
“vestigial” intermediate lobes of telson, a relatively broader cornea as 
indicated by lower L eye/B cornea ratios (and possibly by lower 
L/B cornea ratios). 
Discussion 
There are three populations of Hemisquilla in the Pacific—one 
Australasian and two American. The latter are geographically sep- 
arate (apart from a single juvenile from Panama). 
Four possible morphological differences between the populations 
have been noted: number of segments in the mandibular palp, number 
of intermediate lobes on the telson, relative length of rostrum, and 
relative breadth of cornea. In each case there is considerable vari- 
ability and overlap between populations. 
An initial analysis showed that American and Australasian popu- 
lations are morphologically distinguishable by statistical tests at a 
highly significant level. (These analyses also show hints of sexual 
dimorphism in some features and slight alterations of proportions with 
increasing specimen size.) At this stage one might conclude that the 
American and Australasian forms belong to two subspecies. 
In further analyses a three-way comparison has been made, 
American material being treated under Chilean and Californian 
headings and compared with the Australasian. Of six features 
measured (two being different measurements of rostral proportions and 
two being eye proportions), the numbers of dissimilarities among the 
three populations are shown below. 
highly just or not 
significant doubtfully significant 
significant 
Australasian v. Californian 6 0 0 
Chilean v. Australasian 3 3 0 
Chilean v. Californian 3 1 2 
