Tertiarj/,'] PALiEONTOLOGY OF VICTORIA. IMollusca. 



Plate XXVI., Figs. l-2a. 

 HALIOTIS N^VOSOIDES (McCoy). 



[Genus HALIOTIS (Linn.). Sub-kingd. MoUusca. Class Gasteropoda. Order Scuti- 

 brancliiata. Faiii. Haliotidaj.) 



Gen. Char. — Shell very much depressed, with an ovate or ear-shaped outline formed entirely 

 of the last whorl ; spire extremely small, depressed, close to the posterior left lateral margin ; 

 external surfiice usually rough, with radiating wrinkles and spiral ridges ; a sub-angulated row 

 of short tubular perforations extends from the anterior part of the outer lip, close to the left 

 margin of the shell on the upper side ; outer lip thin, simple ; aperture extremely large, the 

 inner lip forming a flattened inflexed boundary to it on the left side.] 



Description. — Sub-orbicular, depressed ; spire of 2.} turns, moderately promi- 

 nent ; upper surface witb numerous short irreg-ularly interrupted fluctuating' wave- 

 like ridges in radiating series arched forward from the suture, and not regularly more 

 prominent at the distal end ; spiral striaj, thick, sub-equal, rounded, about 12 in 

 the space between the suture and the perforations ; perforations moderately 

 produced, oval, about 4 in 9 lines at IJ inches in diameter, obliquely crossed by 

 fine close strife of growth. Average diameter, 2 inches ; proportional width, -^^yu ; 

 diameter of spire, y^% ; height, -f^^. 



At first sight tliis might be mistaken for that most abundant 

 living species in Australian seas the H. ncevosa (Mart.), and the 

 imperfect preservation of most specimens hel])S to give an erro- 

 neously Recent or Newer Pliocene aspect to the deposits in which 

 it occurs from this apj^arent identity. The numerous examples I 

 have seen, and the character of the siu-flice as given by impressions 

 in gutta-percha which I had taken of the cavities from which the 

 casts of the shell had disappeared, enable me to distinguish it with 

 certainty by its less elongate or more orbicular form, larger spire, 

 and much thicker and fewer spiral striae ; these, in about one inch 

 fi-om suture to perforations, being aljout 60, and much more unequal 

 in the living H. ncevosa^ but only about 13 in the fossil H. ncevo- 

 soides. The living species is longer in proportion to the width, or 

 less orbicular in outline, but agrees in the irregidar ripple-like 

 interrupted character of the arched radiating undulations, not more 

 prominent in the distal end than in the middle, which separate it 

 easily from the H. ovinoides of the Moorabool limestone near 

 Maud. 



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