102 BIOLOGY OF THE RICHMOND RIVER, 



Var. CONICUM, n.var. (PI. iii., f.7rt). 

 Forma brevior, lateribus planis nee retusis, superne etiam quam 

 levissime convexis. 



Long, semicell. 34, lat. 44, ap. 16, isth. 14 /x. 

 Lisinore(12). Cum priori. 



Var. suBCUCUMis (Schm.) mihi. (PI. iii., f.8). 



Long. 70, lat. 46, isth. 14 /x. 



Lismore (12). Cum prioribus duabus. 



Syn. Cos. siihcucumis Schmidle, Schwarz. u. Rheineb., p. 98, 

 T.4, f.20-22; W. & G. S. West, Monog., ii., p.l55, P1.70, f.1-3. 

 Cos. suhcucumis is the result of a double division in Cos. migu- 

 latum f. major, as the figures plainly show. The specimens were 

 all in the same drop. Var. suhcucumis is reniform, suborbicular 

 or approaching to conical according to growth. Dimensions of 

 the mixed forms : — 



1. Cos. ang.ia.): — long. semi. 40, lat. 46, ap. 16, isth. 14 /x. 

 Var. subc.(h): — long, semi 34, lat. 44 /x. (PL iii., f .9). 



2. Cos. ang.v. conic. (a):— long. semi. 34, lat. 44, ap. 16, isth. 14/x. 

 Cos an^. V. SM6citc.(b):~ long. semi. 28, lat. 40/x. (PI. iii., f. 7). 



The size of var. suhcucumis (2b, supra) agrees with the smallest 

 dimensions (54 x 44) given by Schmidle. PI. 70, f.4, of the Mono- 

 graph shows a semicell approximating in outline to Cos. angu- 

 latum var. conicum. 



Cos. suBcosTATUM vai. Beckii (Gutw.) W. & G. S. West. 



Long. 34, lat. 28, ap. 12, isth. 8/x. 



Lismore (12). Plentiful. (PI. iii., f.lO). 



The apex was 4-granulate, but the inner two granules were 

 geminate. None of the Casino forms of this group were noted in 

 the Lismore branch of the river. 



Var. AUSTRAi-E, n.var. (PI. iii., f.ll). 



Formse minori proximum, granulis autem medianis nullis. 

 Semicellulse semicirculares, apicibus angustis 4-granulatis, lateri- 

 bus e basi rectis, superne valde rotundatis, crenis bigranulatis 2, 

 crenis simplicibus basalibus 3. 



Long. 26, lat. 22, ap. 10, isth. 6 /x. 



Casino (14). 



