A FOSSIL ISOPOD OF THE FRESHWATER GENUS PHREATOICUS. 365 



The specimen from which the accompanying plate was 

 made, was collected at Kogarah, by Mr. J. Oorkery, in 

 April, 1916. 



We are indebted to Miss M. Flockton for the drawing. 

 Explanation of Plate XIV. 



a. Yolva showing the membranous whitish cup and lobes in situ. 



b. Membranous cup and lobes dissected. 



c. Yolva opened out to show the arrangement of the membran- 



ous cup and lobes. 



A FOSSIL ISOPOD BELONGING TO THE FRESH- 

 WATER GENUS PHREATOICUS. 



By Ohas. Ohilton, m.a.,d.Sc, m.b.,c.m.,ll.d., f.l.s.,c.m.z.s., 



Professor of Biology, Canterbury College, New Zealand. 



(Communicated by R. J. Tillyard, m.a., etc.) 



[Bead before the Royal Society of N. S. Wales, October 3, 1917.'] 



CONTENTS. 



1. Introduction. 



2. Description of Specimens. 



3. Diagnosis of Fossi] Species. 



4. Historical Account of the Phreatoicidea. 



5. Other Fossil Isopoda. 



6. Analogy with the Anaspidaeea. 



7. List of Works referred to. 



1, Introduction. 

 In May, 1917, Mr. R. J. Tillyard, who is investigating 

 the Mesozoic and Tertiary Insects of Queensland and New 

 South Wales, wrote to me saying that among the fossils 

 from the Wianamatta Shale of St. Peter's Brickworks, 

 Newtown, Sydney, New South Wales, he had several speci- 



