758 AUSTRALIAN CRUSTACEAN FAUNA. 



three types of pleon. He styles them : — Males, females, and 

 " spurious females." Some later writers, taking into consideration 

 the already cited case of Stenorhynchics fhalangium, have taken 

 it for granted that the conclusions arrived at there would appl}' 

 equally as well to all of the species in which three types of pleon 

 obtain; but, as I have shown, they cannot be applied to the form 

 under consideration. 



In the foregoing remarks I have, as before stated, only referred 

 to the genus Neptuniis, but I feel sure that others amongst our 

 native genera will be found to possess these sterile females. At 

 present there are two species which I have good reason to believe 

 agree in this manner with Neptunus. viz., Ozius truncatas and 

 Platyonycltiis bipustulatus. The former lives among loose stones 

 in rocky situations, whilst the latter, though really pelagic, 

 spends most of its time half buried in the sand in shallow water. 



I here desire to tender my sincere thanks to Mr. Jas. P. Hill, 

 Demonstrator of Biology, for some kindly criticism during the 

 course of my work; also to my friend. Mi". R. Grant, Physiological 

 Laboratory, University of Sydne}', for assistance most willingly 

 rendered in various ways; and lastly, to Mr Whitelegge, Aus- 

 tralian Museum, for assistance with the literature relating to the 

 subject. 



