Foramlnifera and Ostracoda. 201 



angle, and an obliquely rounded antero-dorsal. A thick flange 

 runs round the front margin, especially developed towards the 

 ventral angle ; a similar one is seen on the sub-acute posterior 

 extremity. Highest in the anterior third. Edge view of cara- 

 pace ovate, tumid. Valve edges closely adpressed but not 

 overlapping. End view sub-cordate. Surface of valves perfectly 

 smooth. A group of ovoid muscle spots closely arranged around 

 a ringlike centre is seen in the middle of each valve. 



Measurements. — Length, 0.7 mm.; greatest height, 0.35 mm.; 

 thickness of carapace, 0.34 mm. 



Remarks. — Most of the known species described under this 

 genus are recent forms, but Dr. G. S. Brady remarks' that, 

 " many fossil species described by authors under various generic 

 terms — ^Cythere, Cytherina, Bairdia, etc. — belong by rights to 

 Loxoconcha." 



The specimen figured here is probably a female, having regard 

 to the comparative tumidity of the carapace, and its well-rounded 

 angles. 



Occurrence. — Rare ; Jurassic, Greenough River district, West 

 Australia. [2152.] 



Loxoconcha jurassica, sp. nov. (PI. XXIIL, Figs. 6, 6^ 6/^). 



Specific characters. — Valves seen from the side, sub-rectangular; 

 hinge-line slightly concave. Ends lipped and well rounded, the 

 antero-dorsal angle obliquely curved. Surface of valve rising 

 towards the postero-ventral, and forming a protuberance in that 

 region. Edge-view depressed-ovate. End view sub-cordate. 

 Surface of carapace ornamented with a few interrupted striae 

 parallel with the ventral margin. 



Measiiremetits. — Length of valve, 0.43 mm.; greatest height, 

 0.21 mm.; thickness of carapace, 0.21 mm. 



Affinities. — This species has the same general features as G. S. 

 Brady's L. variolata,'- although it differs from it considerably in 

 certain respects, such as the linear arrangement of the surface 

 pittings. Brady's species is found fossil in tertiary strata, and 



1 Rep. Chall. Zool., 1880, vol. i., pt. iii., p. 116. 



2 Trans. Zool. Sec, vol. x., pt. 8, 1878, p. 400, pi. Ixviii., figs, ia-d; Kep. Chall. Zool., 

 torn. sup. tit., p. 121, pi. xxix., flgs. 6a-d. 



