62 Transactions. 



the basis : basis membranous : scutum transversely elongated : tergurn 

 small, with the spur extremely short and rounded." (Darwin.) 

 Locality.— Otago (W. R. B. Oliver). 



Elminius modestus Darwin. 



Elminius modestus Darwin, 1854, p. 350, pi. 12, figs, lo-le ; Hutton, 

 1879, p. 328 ; Gruvel, 1905, p. 296, figs. 319-322 ; Pilsbry, 1916. 

 p. 261. Elminius sinuatus Hutton, 1879. p. 328 ; Gruvel, 1905, 

 p. 295. 



Specific Diagnosis.— "' Shell folded longitudinally, greenish or white : 

 radii of moderate breadth, smooth-edged : scutum without adductor ridge : 

 tergum narrow, with the spur confluent with basi-scutal angle." (Darwin.) 



Localities. — Lyttelton Harbour (L. S. Jennings) ; Riwaka, Nelson Har- 

 bour (L. S. -Jennings) ; Takapuna Beach ; Half-moon Bay, Stewart Island 

 (W. R. B. Oliver) : Ponui Island, Hauraki Gulf (C.' Chilton). 



E. sinuatus Hutton is probably only a variety of E. modestus Darwin. 

 In groups of E. modestus many young specimens have parieties of each 

 valve with two rounded folds, referred to by Hutton in his description of 

 E. sinuatus. The two distinct folds show also when specimens are not 

 crowded together. 



Elminius plicatus Gray. 



Elminius ■plicatus Gray, 1843, Appendix to Dieff enbach 's Travels in 

 New Zealand, p. 269 ; Darwin, 1854, p. 351, pi. 12, figs. 2a~2f ; 

 Hutton, 1879, p. 328 ; Gruvel, 1905, p. 296, figs. 318, 321 ; Pilsbry, 

 1907, p. 261. 



Specific Diagnosis. — '' Shell deeply folded longitudinally, corroded, 

 coloured in parts orange : radii very narrow, with their edges sinuous, and 

 slightly dentated : scutum having an adductor ridge." (Darwin.) 



The valves show many variations in elongation of terga, prominence of 

 grooves and ridges, straightness of tergal articular ridge, length and inflexion 

 of tergal furrow, bluntness or beaked nature of apex. 



The general appearance of the shell is also extremely variable. When 

 very corroded the walls are extremely thick, by the inward production of 

 the internal ridges, giving an appearance of porosity. These specimens 

 are usually depressed, and are of a grey or dirty-white colour. 



Localities. — ICaipara Harbour (Spencer) ; Shag Point, Otago (W. R. B. 

 Oliver) ; Lyttelton Harbour (L. S. Jennings) ; Puhoi Beacon, Auckland 

 Harbour (C. Chilton) ; Hawera (L. S. Jennings) ; Ponui Island, Hauraki 

 Gulf (C. Chilton) ; Oamaru (L. S. Jennings) : Takapuna, Auckland 

 (W. R. B. Oliver). 



Coronula diadema (Linnaeus). 



Lepas diadema Linnaeus, 1767, Systema Naturae, ed. 12, p. 1109. 

 Coronula diadema, Darwin, 1854, p. 417, pi. xv, figs. 3, 3a, 3& ; 

 pi. xvi, figs. 1, 2, 7 : Hutton, 1879, p. 329 : Gruvel, 1905, p. 273 : 

 Pilsbry, 1916, p. 273, pi. 65, figs. 3, 4. 



Specific Diagnosis. — -" Shell crown-shaped, with longitudinal convex ribs, 

 having their edges crenated ; orifice hexagonal : radii moderately thick, 

 very broad : terga absent or rudimentary." (Darwin.) 



Localities. — Waikouaiti, on a whale (F. W. Hutton) ; on whale (speci- 

 mens in Auckland Museum). 



