30 Frederick Chaptnan: 



with a broad border marked with radial lines; posterior with 

 a narrow depressed margin. Seen from above, carapace ovate, 



• compressed at the extremities, with a hooked process prominent in 

 the median area. Rising from the middle of each valve, a little 

 in front and towards the ventral margin, the hooked process is 



:seen to curve towards the dorsal border. BeloAv this, nearer the 

 ventral margin, is a rounded prominence or tubercle, and near 

 the dorsal margin, anteriorly and medially are two others, 

 Superficial ornament consists of fine reticulae or pittings scattered 

 closely over the larger part of the valves. 



Length, .38 mm.; greatest width, .3 mm.; thickness of carapace, 

 .27 mm. 



Observations. — None of the northern species very closely ap- 

 proach the above form, the nearest being L. monstrifica, Norman 

 sp.,8 found living round England, and Pleistocene in the Lincoln- 

 shire Fens. This has two large spinous processes, with several 

 smaller spines and ridges. Undoubtedly the nearest allied species 

 is the Limnocy there mowhrayensis, Chapman,^ which the writer 

 recently described from Mowbray Swamp, near Smithton, N.W. 

 Tasmania. In this species, the lateral processes are not so produced, 

 the tubercles differently spaced, whilsti the anterior border is not so 

 deep nor broad. Moreover, it attains a larger size than the present 

 . species., 



Occurrence. — This very minute species is excessively abundant 

 in the Boneo Swamp deposit. 



General Remarks and Summapy. 



An examination of the swamp deposit from this locality in the 

 Schanck Peninsula affords some interesting points for comment. 

 Probably in late Pliocene times, and on to Pleistocene, this area 

 was connected with Tasmania. The immediate progenitors of the 

 freshwater mollusca and ostracoda found in the Boneo deposit 

 must have been living in dune and swamp country, which no 

 • doubt extended across Bass Strait. We can conceive this country 

 then connected by way of a chain of swamps running from, the 



8. Cypris monstrifica, Norman, Ann. Mag. Nat. Hist., Vol. IX., 1862, p. 45, 

 pi. III., Pigs. 4, 5. Limnicythere monstrifica, Norman sp. Brady, Mon. 

 Rec. Brit. Ostrac, 1868, p. 420, pi. XXIX., Figs. 9-12. 

 •9. Mem. Nat. Mus., Melbourne, No. 5, 1914, p. 60, pi. II. Figs. 8a-c. 



