W. H. Hudlcston — Fossil Shells from South Australia. 245 



reference made to P. laticostata, Stol., Cret. Kocks India, Pelecypoda, 

 Pal. Indica, vol. iii. 1871, p. 385, pi. xxv. fig. 2-3, and xxvi. fig. 4. 

 The specimen figured is from a sandy bed at Primrose Springs. 



Mytilus, sp. Plate IX. Fig. 9. 



This is a true Mytilus, the umbones being terminal. It is dis- 

 tinguished by the marked convexity of the upper or hinge border 

 and a corresponding incurvation of the lower margin. There is no 

 shell left ; but, to judge from indications on the cast, broad concentric 

 lines constituted the principal ornamentation. 



This cast is perhaps somewhat too compressed for Mytilus rugo- 

 costatus, Moore, and both margins are rather arcuate. 



There are no indications as to locality with this specimen, which 

 probably comes from the Lake Eyre district. 



Mytilus linguloides, Hudleston, 1884. 



1884. Modiola linguloides, Hudl., Geol. Mag. Dec. III. Vol. I. p. 341, PI. XI. 

 Fig 6. 



I take this opportunity of pointing out that Mod. linguloides is 

 really a Mytilus. Large specimens of this species occur 45 miles 

 South- West of Coattonoona Station in the Lake Eyre district. It 

 may possibly be the same as Mytilus inflatus, Moore, (op. et vol. cit. 

 p. 252, pi. xiii. fig. 4), but would seem to run larger and to be 

 somewhat less inflated than Moore's species. 



Modiola subsolenoides, sp.nov. PI. IX. Fig. 8. 



Length from umbones to lower border about 55 mm. Umbones 

 rather blunt ; umbonal ridge much thrown back towards the dorsal 

 or hinge-border. Shell subelongate and gibbous ; anterior area 

 straight and marked by rugose concentric lines, which are much 

 less strongly developed in the dorsal or hinge area, which slopes 

 from the umbo, and curves round to meet the posterior extremity. 

 This latter is considerably dilated, being 2^ times the width of the 

 anterior extremity. 



This species possesses considerable resemblance to Myoconclia, 

 but the shape of the umbones and the sulmacreous character of the 

 inner layers of shell are against this supposition. In figure it 

 possesses a general resemblance to " Mytilus " solenoides, Morris and 

 Lycett (Great Oolite Moll. Biv. p. 38, pi. iv. fig. 1). 



No locality is recorded, but it probably comes from the neigh- 

 bourhood of Lake Eyre. 



Thracia primula, sp.nov. PI. IX. Fig. 7. 



Length to width about as 5 : 3 - 5. Shell extremely thin, subovate, 

 and but slightly inequivalve, extremely compressed. Umbones a 

 little posterior, and giving rise to a slight curvilinear ridge in the 

 posterior area. Anterior side suborbicular, posterior extremity 

 squarely truncate. Breadth of anterior to posterior side as 3:2. 

 The ligament is well developed, and occupies one-third of the length 

 of the posterior dorsal margin. Kather broad concentric lines of 

 growth ornament the shell. 



