part 3] THE TEIAS OF NEW ZEALAiND. 205 



anteriorly situated and directed forwards, not projecting above the 

 hinge-line. There is a curved truncation in front of and below 

 the beak of the right valve, which extends for about a third of the 

 length of the anterior margin and is bounded posteriorly by a raised 

 ridge, on and behind which three or four faint radial ridges occur. 

 The tongue-like projection of the right valve is directed towards 

 the opposite valve at about a right angle from the plane of the right 

 valve. ■ The posterior wing is angular and flattened. The hinder 

 marghi is gentl}^ curved, the anterior margin more rounded, and 

 the lower margin is well rounded. The growth-lines are prominent 

 and irregular, and the surface of the shell towards the lower margin 

 tends to become wavy and irregular. 



Height =75 mm. ; length = 58 mm. ; length of the hinge-area =: 

 27 mm. ; depth of right valve = 18 mm. 



Locality and horizon. — Bed c, Otamita, Hokonui Hills, 

 Carnic. 



Kemarks. — This is the most Lima-Yike of these shells, and 

 recalls in general outline the recent Lima excavata. I have three 

 right valves, all with portions of the shell; one of them with 

 the left valve attached but lacking the beak ; and a separated 

 left valve. 



Hoko:n'UIA EOTUis^DATA, sp. nov. (PI. XX, figs. 5 « & 5 5; 

 PI. XXII, figs. 1, 3, & (?) 4 a, 4 h.) 



Shell fairly thick, valves rather inflated and gently rounded, 

 about as high as wide. Hinge-line considerably less than the width 

 of the shell. The beak projects somewhat above the hinge-line, 

 and is situated about the median line or rather in front of it. The 

 posterior wing is rounded in outline, and is scarcely differentiated 

 from the hinder margin of the shell, which is gently rounded. 

 The anterior margin is rounded and rather produced, and the lower 

 margin is gently rounded. There is a short, anterior, semicircular 

 truncation below the beak of the right valve. 



Growth-lines are well marked, and irregular ripples of growth 

 occur especially towards the mai-gin. 



The anterior tongue-like process of the right valve is directed 

 forwards, rather than directly downwards, away from the I'ight 

 valve. 



A specimen with both valves measures 89 mm. in height and 

 84 mm. in length ; the right valve is 21 mm. deep, and the hinge- 

 line is 35 min. long. 



Locality and horizon. — Hokonui Hills. I have casts of 

 two left valves, and another cast in which both valves are slightly 

 displaced. I collected a left valve with the shell on it in the 

 Mijt il as-prohl ematicus Bed at Nugget Point. The New Zealand 

 Geological Survey possesses a cast of the anterior part of a right 

 valve, from which I made. a gutta-percha squeeze. Carnic. 



Remarks. — This species is more rounded in outline than the 

 last ; the anterior truncation of the right valve is less extensive 

 and more curved ; and the tongue-like process is directed more 

 forwards from the plane of the valve. 



