NO. 3564 HEMISQUILLA ENSIGERA—STEPHENSON 9 
Table 1 shows that there is equivalent variability in Australasian 
and American material and that the rostra of American specimens are 
significantly longer than that of the Australasian (p. < 0.001). 
Inspection of data indicated possible sexual dimorphism and size 
effects. Relevant data on sexual differences are shown below. 
L/B rostrum 
no. mean weighted mean 
Australasia 60S 1.1017 1.1021 
239 9 1.1026 
America 280'o' 1.3086 1.3027 
169° 1.2925 
L carapace/L rostrum 
no. mean weighted mean 
Australasia 36d0S 4.7292 4.7746 
2399 4.8457 
America 28'S 4.1289 4.1534 
169° 4.1963 
For L carapace/L rostrum data the differences between male and 
female means is significant almost at the 0.02 level on Australasian 
material but not significant on American (p ca. 0.3). No tests were 
carried out on L/B rostrum data because of the small differences 
between means of Australasian males and females, respectively, and 
the reversed tendency of Australasian versus Californian data. 
The effects of size upon the ratios were only investigated upon 
L/B rostrum data, which appeared to offer the more ‘“ promising” 
indications. Correlation coefficients between carapace length and 
L/B rostrum for Australasian and American material are —0.070 
and +0.330, respectively. The former is not significant (p >0.1), 
while the latter is significant at about the 0.03 level. Regression 
coefficients between carapace length and L/B rostrum are —0.00156 
and +0.00479, respectively. 
Summarizing these analyses, the American and Australasian 
specimens clearly belong to different populations with shorter rostra 
on the Australasian material. There are indications of sexual di- 
morphism, with a smaller L carapace/L rostrum ratio in males, but 
this is significant only on Australasian material. There are also 
indications of a slight size effect, which is significant only on American 
material. 
Eyrs AND EYESTALKS.—This possible distinction, like the last, 
arose initially by comparison of Australasian specimens with Kemp’s 
figure (1913, pl. 7, fig. 84) of a Chilean specimen. 
Measurements were made on all undamaged eyes of length of 
eyestalk from lateral view, length of entire eye from lateral view, 
221-528 67-2 
