46 AMPHINETJRA. [Polyplacophora. 



mens a good hand-lens shows the series of ocular punctures along the 

 diagonal ridge, immediately in front of the anterior row of pustules. 

 (Pilbry.) 



Australia and New Zealand only. 



m 



Sect. 1. LORICA, s. str. 



Sinus in tail valve deep ; jugal sinus V-shaped ; girdle widest at 

 the sides, cleft behind. 



1. Lorica volvox, Reeve, 1847. Plate 2, fig. 22 ; Plate 5, figs. 3, a, b. 



Chiton volvox, Reeve, Conch. Icon., Chiton, pi. 6, f. 31. Lorica volvox, 

 Reeve, Man. Conch. (1), xiv, 237, pi. 52, f. 14-21 ; P. Mai. 8., vii, 297. 

 C. cimolius. Reeve. Conch. Icon., pi. 21, f. 141. C. (Lepidopleurus) rudis, 

 Hntton, T.N.Z.I.. iv. 1872. 179. 



Shell oblong, strongly elevated, the dorsal ridge angular, side 

 slopes nearly straight ; surface lustreless, finely sculptured, variable 

 in colour. Anterior valve strongly elevated, curving forward at the 

 summit, the anterior slope being concave ; sculptured with many 

 radiating riblets, which are pustulose when not eroded. The median 

 valves are not beaked even when young, but they are falsely beaked 

 or narrowly projecting at the sinus in front ; lateral areas raised, 

 sculptured with 8-12 low radiating cords bearing rounded pustules, 

 which are more or less entirely lost in adult specimens ; central areas 

 sculptured with numerous narrow raised threads parallel to the dorsal 

 ridge, their interstices wider than the threads, and closely latticed 

 across. Posterior valve small, much depressed, with posterior terminal 

 elevated mucro ; posterior lateral margin bounded by an elevated rib ; 

 posterior area extremely small, vertical, perpendicularly ribbed, having 

 a deep rounded excavation behind. Girdle wide, bluish with incon- 

 spicuous dusky cross-bars, slit behind, its surface very densely covered 

 with minute, closely imbricating, smooth, convex scales. Colour some- 

 times buff, with chestnut streaks and darker angular blotches on the 

 central areas, fewer on the lateral areas ; sometimes the lateral areas 

 are olive-green, the dorsal region light, the sides of the central areas 

 brown or olive. The dorsal ridge is sometimes stained with orange 

 on each valve, and the same colour often clouds the sides also. In- 

 terior white ; tegmentum reflexed and sculptured along the posterior 

 margin of each valve ; anterior valve having 8 slits, central 1 slit ; 

 the slits minute ; teeth short, blunt, finely but obsoletely pectinated 

 outside, and crenulated at the edge. Posterior valve having a low, 

 rounded callus ridge in place of the insertion plate, its edge unslit, 

 finely and rather obsoletely striated, interrupted by a deep rounded 

 sinus in the middle behind ; eaves narrow, solid ; sutural plates 

 broad, separated by an extremely small V-shaped sinus in the middle. 



Length, 70 mm. ; breadth, 38 mm. Divergence, about 90 ; the 

 young more depressed. (Pilsbry.) 



