460 Transactions of the Society. 



Metopidia ehrenhergi Perty {13). Plate XIX, fig. 8. 



Hahitat. — Pond in Sydney, associated with M. heterostylct ; 

 several examples. 



All the Sydney specimens are heterostylous, as are some from 

 the United States, which I have seen in Mr. Eousselet's collection. 



Metopidia quinquecostata Lucks {8). Plate XIX, fig. 9. 



Hahitat. — Pond in Sydney, associated with the previous two 

 species on our list. 



It is figured here because either Lucks' figjures srive a wroncr 

 idea of the general appearance of the animal, or the Australian 

 form is very different from the type. 



Lucks' figure is of a broadish animal, broadly truncate behind. 

 The Sydney animal is of graceful form, much narrower and elon- 

 gate, with only a small truncation, the ventral opening for the 

 foot much longer and narrower. The ribs are very prominent 

 hyaline walls, which end far from the posterior border, except 

 only the middle one. 



My drawing is poor, but gives the correct proportions of my 

 specimens. 



Mfdopidia collaris Stokes {15). 



Two collared forms (at least) have been described. Stokes' 

 description is inadequate, but I identify the Australian form with 

 it, because Levander's collaris is considered as a variety of M. 

 lepadella, and the animal I know is not related to that species, 

 being much smaller. I have not been able to figure it here. 



Pterodina striata sp. n. Plate XIX, figs. Aa-M. 



Specific Characters. — Of moderate size, shortly pyriform, the 

 anterior end narrower. Surface irregularly punctate all over. 

 Anterior dorsal marM formingr an obtuse anole in the middle 

 line, crenate, ventral margin with a very deep V in the middle. 

 Xarrowed anterior part of lorica striate. Foot opening shortly 

 oval, nearly central. Margin of lorica very thin. 



Length of lorica 170 /jl, breadth 136 /x, of anterior opening 45/^. 



The preserved specimens are yellow, which may be due to the 

 preservative. The dots make an obscure reticulation, as shown in 

 fig. 4:d. The whole dorsal surface appears to be minutely wrinkled, 

 as appears near the margin in fig. 4a. The lorica is so thin near 



