EBOHHOCB] i' 



I. coNTSAcrua Reeve, I'l. 23, figs. 81, g 



Shell oblong, peculiarly runt ractrd ;it tin- rxhvn 

 especially tin* anterior; terminal valves and lateral 

 tin- rest concentrically granulated, granule^ solitary, central 

 areas very minutely and closely ridded, ridges curved and OOD- 

 spicuous towards the >idcs, finer towards the middle and drniat-d 

 with ohli(|iie stria-: light hay, flamed in the middle with hrown ; 

 ligament granosely coriaceous, dark hrown. (live.) 



TiH*innniii Mil-. ( 'inn 



( '/ilton contractus KEEVE, Conch. Icon. 1. 1^, fi;r. 7*, March, 1847. 

 ( 1 hiton. (IcciiMttH* RI:I:\ I-;, Conch. Icon. t. 18, f. 107, April, 1> 17. 

 Chiton rattu* IvVK., t. 22, f. 14-"), May, 1847. /.>'/, n^-hitn,, 

 castus CPR., MS., and 7. interyranosus CPR., MS. Lr/, ;<!<,/, /, 

 .^Hclosus H. AD. & ANGAS, P. Z.S. 1864, p. \'2 ; /. r., 1S T), p. 187. 



This species has heen several times described, but the range of 

 variation seems to be less than in some other allied forms, although 

 the coloring varies considerable. The acute dorsal ridge, divergent or 

 zigzag sculpture of the dorsal areas, the granulation of the lateral 

 areas and serration of the sutures are characteristic. The descrip- 

 tions of the several forms included under contractus follow below. 



Carpenter's notes are as follows: shell oval, subelevated, ashv, 

 irregularly streaked with brown-olive. Otherwise like /. c</ 

 but the central areas are everywhere zigzagly wrinkled, the lines 

 which in castus are conspicuously at right angles to the diagonal 

 line are not seen in contractus. Lateral areas and end valves hav- 

 ing close radiating wrinkles, more or less broken into granules con- 

 centrically, sometimes scarcely at all, sometimes entirely so. Inte- 

 rior: anterior valve having 14, central valve 1, posterior valve 13 

 slits; teeth acute; eaves conspicuous, hardly spongy; sinus wide, 

 flat, smooth ; it appears broader and the sutural lamina? not so high 

 as in castus. Girdle pale black-brown : scales as in 7. nidus. 

 Length 37, width 17^' mill.; divergence 110. 



There are 3 specimens in the Cuming collection, from Tasmania, 

 and two on the same tablet which are really an intermediate variety 

 of I. castus. I cannot see the contracted sh a j H' figured hy Keeve, 

 in either of the specimens, which are shaped just like 7. /<i</ici/ml>a. 

 The streaked coloring is quite exaggerated : it is very irregular, not 

 in even lines as in Reeve's figure. The divergence is the .-ameasin 

 7. castus. Side by side they exactly correspond. The difference 



