CALLOCHITON. 51 



rounded at the margins, sometimes (abnormally?) pectinated. 

 Entire surface conspicuously but minutely granulated. 



Interior : Posterior valve having 17, anterior 18, median valves 

 3 slits. Teeth elegantly radiately propped, curved outward, two or 

 three lobed, sometimes striated. Eaves short, reddish, spongy. 

 Inside light flesh colored. Sutural plates joined, broadly but 

 slightly sinuated in the middle. Girdle normal. (Cpr.) Length 

 32 J, breadth 20 mill. ; divergence 135. 



Habitat unknown. (Mus. Cum. No. 95.) 



The complicated external structure of the insertion plates is more 

 beautiful in this than in any other known species, resembling the 

 fret-work of a Gothic pinnacle. It is specially displayed where the 

 eaves have been broken off through accident, and the grooving is 

 displayed under the colored part of the valves, which are there pec- 

 tinated at the edges. It is unfortunate that the locality of this 

 typical species is unknown. (Qor.) 



C. ILLUMINATUS Reeve. PL 9, figs. 92, 93, 94. 



Shell oval, red, rather elevated, the jugum acute ; umbo a little 

 in front of the middle, slightly elevated. Entire surface very min- 

 utely wrinkle-striate and granulose under a lens, the central areas 

 longitudinally, the rest radially. Central areas with slender ele- 

 vated separated threads, parallel to the jugum, 6 to 14 on each 

 side. Lateral areas rather elevated. 



Interior roseate. Anterior valve with 15-16, posterior with 11-14 

 slits, median valves with 1 slit. Teeth acute, quite distant, scarcely 

 propped. Eaves spongy, sinus small, the sutural plates connected 

 across it. Girdle normal, the scales rather large, solid ; sometimes 

 spotted with paler at the sutures. (CJpr.) 



Length 16, breadth 10 mill. ; divergence 120. 



Straits of Magellan. 



Chiton illuminatus REEVE, Conch. Icon. t. 22, f. 147,1847.-- 

 C. (Callochiton) illuminatus Rve., SMITH, P. Z. S. 1881, p. 35. 

 Lepidopleurus illuminatus ROCHEBRUNE, Miss. Cap Horn, p. 141. 



There are about 16 gill plumes on each side, reaching three-fifths 

 of the distance forward, according to Carpenter. In having but 

 one slit in the median insertion plates and in the want of props on 

 the teeth this species is abnormal ; in other respects it agrees with 

 Callochiton. 



