NO. 3564 HEMISQUILLA ENSIGERA—STEPHENSON 11 
dimensions of eyes and eyestalks (broader cornea in Australasian 
material). Of four possibilities of sexual dimorphism, only one is 
significant—L eye/B cornea in Australasian males, greater than in 
females. The ratio L/B cornea increases significantly with specimen 
size. 
The general summation of the results of the present section is that 
Australasian and American material are significantly different in all 
features selected for examination. In the six sets of data, differences 
between means are significant at p levels of <0.001. Apart from 
differences in means there are also differences in the form of frequency 
distributions of deviations from mean (e.g., skewness) and in hetero- 
geneity within groups. There are indications of sexual dimorphism 
in certain features and stronger indications of proportions changing 
with specimen size. Since none of these effects are as noteworthy as 
those depending upon locality, they were neglected in further analyses. 
Comparisons Between Californian, Chilean, and Australasian Material 
Because differences between American and Australasian populations 
had proved so highly significant and because in many respects mean 
values for Chilean material lay between Californian and Australasian 
extremes, data were reconsidered under the three main locality group- 
ings. Results, given in tables 2 and 3, show that differences between 
Californian and Australasian data are highly significant throughout. 
Further consideration is restricted to Australasian/Chilean and 
Chilean/Californian comparisons. 
MANDIBULAR PALP.—The mean Chilean value is roughly midway 
between Australasian and Californian means, with an approximately 
equal probability of the differences being significant (p ca. 0.1 and 
0.2 — 0.1, respectively). The three populations have approximately 
equivalent variability. The Californian data is more skewed than 
the Chilean data. 
INTERMEDIATE LOBES OF TELSON.—The mean Chilean value lies 
further from the Australasian than the Californian and differs sig- 
nificantly from the Australasian (p ca. 0.01) but not from the Cali- 
fornian (p 0.4 — 0.3). The Chilean data resembles the Californian 
in the form of its frequency distribution; both differ from the skewed 
curve for Australasian data. Variability in the Australasian data is 
much higher than in the Chilean, which resembles more that of the 
Californian. 
RostRAL PROPORTIONS.—L/B rostrum: The mean Chilean value 
is closer to the Australasian than to the Californian. It is not sig- 
nificantly different from the former (p ca. 0.2) but is from the latter 
(p <0.001). The variability of the Chilean values is of the same 
