EXPLANATION OF PLATE XXVIII. 



Martiiiiopsis strzelecki, de Knninrl-. 



Fig. 1. Brachial valve aud portion of pedicle valve exhibiting the slits 

 left by the decay of the dental plates in the pedicle valve, 

 and those of the septal plates in the brachial valve. A cast 

 from the Upper Marine Series of Nowra Hill, Shoalhaven, in 

 the Berry School of Arts. 



Martiniopsis subradiata. 



,, 2. Portion of weathered test of a specimen of Martuiiopsis 

 snhradiata, from Farley, exhibiting lines radiating in two 

 directions enclosing acutely rhomboidal spaces, highly 

 magnified. 



,, 3. A similar specimen of this species from Fai'ley exhibiting long 

 tear-like tubercles which apparently represent the junctions 

 of the converging lines seen in Fig. 2, highly magnified. 



Dielasma jervisensis, Eth.Jll. 



,, 4. Cast of a bi^oad oval brachial valve of low convexity, a vei-y un- 

 common form of the genus. Cabbage Tree, Jervis Bay. 



Martiniopsis subradiata, vitr. branxtoneusis, EtJi. pi. 



,, 5. Bi^achial valve aud umbo of the pedicle valve of a dwarf form, 

 representing the average size attained by the variety. 



,, 6. Pedicle valve of the same. 



Mtvonia morrisii, Etii.jil. 



,, 7. Latei^al view of right valve, with patches of test remaining, short, 

 gibbous, and prominent diagonal ridge. Harper's Hill. 



,, 8. Cardinal or dorsal view of the united valves of the same sjieeimen ; 

 the strongly curved prominent I'idges are well displayed. 



Platyschisma rotuiidatnm, rnr. farleyensis, Eth. fd. 



,, 9. Internal limonitic cast, exhibiting tlie average normal size of 

 the variety with the sulci resulting from the inwai'd }n'otrusion 

 of t)ie shelly ril)s. 



