ELMINIUS PLICATUS. 351 



cirri resemble those of E. Kingii ; the segments in the sixth pair are 

 equally elongated, and bear five or six pairs of spines. 



Affinities. — This species is closely allied to its South American re- 

 presentative E. Kingii; the differences consist in its smaller size, 

 often greenish colour, more folded walls, and narrower radii : the 

 internal basal edges, also, of the parietes are here smooth, instead of 

 being striated, as in E. Kingii. The terga present even more obvious 

 differences, in their narrowness, channelled under surface, and in the 

 absence of the spur, or more properly in its confluence with the basi- 

 scutal angle of the valve. 



3. Elminius plicatus. PI. 12, fig. 2 a — 2/. 



Elminius plicatus. J. E. Gray. Appendix to Dieffenbach's Travels 



in New Zealand, p. 269, 1843. 



Shell deeply folded longitudinally, corroded, coloured in 

 parts orange * radii very narroio, ivith their edges sinuous, 

 and slightly dentated: scutum having an adductor ridge. 



jjal^ — N ew Zealand ; New South Wales (?). Attached to rocks, often coated 

 by Chamasipho columna; Mus. Brit, and Cuming. 



General Appearance. — Shell tubulo-conical, or conical, rarely de- 

 pressed ; strong, rugged, coloured in parts bright orange ; deeply 

 plicated longitudinally, but with the upper parts corroded and smooth. 

 Orifice large. The sutures are indistinct and almost obliterated ; the 

 radii, when most developed, are narrow. Some specimens have their 

 whole surface deeply corroded ; in which case they are finely striated 

 longitudinally, or pitted, and are of a gray or brown colour. The 

 largest specimens are one inch in basal diameter, but one depressed 

 specimen was 1*3 in diameter; another was rather under one inch in 

 diameter, and one inch in height. 



Scuta ; beginning with the common tubulo-conical and not much cor- 

 roded specimens, the valve (fig. 2 c) is moderately elongated, but in a 

 rather variable degree. A prominent adductor ridge runs, from a little 

 above a middle point of the basal margin, along the slightly prominent 

 articular ridge : the articular furrow is moderately wide. There are 

 distinct crests for the lateral depressores. In the conical, corroded 

 specimens, the scuta (fig. 2 e) are considerably broader, with the arti- 

 cular ridge much more prominent, and the furrow wider : in one such 

 specimen, there were crests for the rostral depressor muscle. 



The Terga, in the commoner variety, resemble those of Tetraclita 

 porosa; the spur adjoins the basi-scutal angle of the valve: the arti- 

 cular ridge is moderately prominent, and the furrow moderately deep. 

 The valve is beaked, with an unusually large internal tube for the 

 thread of corium : the beak, however, is often worn away. In the 

 depressed much corroded specimens, the terga (fig. 2f), like the scuta, 



