12 AMPHINEURA. [Polyplacophora. 



Genus 2. CALLOCHITON, Gray, 1847. 



Callochiton, Gray, P.Z.S., 1847, 126, 168. Type : Chiton Icevis, Montagu. 

 Not Callochiton of Carpenter's earlier writings (P.Z.S.. 1865, 276, &c.) 

 = Callistochiton. Clathropleura, Thiele (part). Bull. Soc. Mai. Ital., iii, 

 1877, 136. 



Valves exposed ; insertion plates rising out of porous or spongy 

 eaves, and cut into numerous teeth ; sutural plates connected or 

 continuous across the shallow jugal sinus. 



The species are not numerous ; they occur in the British seas, 

 the Mediterranean, the Gulf of Manaar, Straits of Magellan, Chile, 

 Australia, Tasmania, New Zealand, Cape of Good Hope, Reunion, 

 Mauritius, Arctic station " Gauss." 



Littoral to 130 fathoms. 



Subgen. CALLOCHITON, s.s. 



Girdle covered with a smooth compact layer of very small diamond- 

 shaped scales. 



KEY TO SPECIES. 



a. Entire surface delicately shagreened . . . . platessa. 

 aa. Central areas distinctly sculptured. 



b. A row of deep pits in front of the lateral areas . . . . empleurus, 

 bb. Central areas with 4-5 deep grooves on each side ; median 



valves with 2 slits . . . . sulculatus. 

 bbb. Central areas with elevated separate longitudinal threads ; 



median valves with 1 slit . . . . puniceus. 



1. Callochiton empleurus, Hutton, 1872. Plate 3, fig. 6. 



Chiton empleurus, Hutton, T.N.Z.I., iv, 178. C. crocinus, Reeve : Pilsbry, 

 Man. Conch. (1), xv, 67, not of Reeve. C. empleurus, Hutt., P. Mai. S., ii, 

 185 ; J. Mai., xii, 65, pi. 9, f. 1-4. 



Shell small, elongated oval, subcarinated, slopes very slightly 

 convex ; flesh-colour, with a squarish white patch on the posterior 

 part of the jugal tract. Anterior valve almost smooth, but minutely 

 punctate and with numerous small eyes, anterior margin with square 

 white spots at irregular distances, and faint traces of radiate riblets ; 

 posterior margin with a median notch. Intermediate valves with the 

 central area minutely punctate, the jugum mostly smooth, with a few 

 transverse shallow furrows, on the central areas in front of the anterior 

 edge of the lateral areas 9-10 deep pits on each side, which are getting 

 shorter and shallower towards the median part of the valve ; lateral 

 areas raised, distinct, with well-pronounced concentric ridges : the 

 eyes are very numerous. Posterior valve rather indistinctly minutely 

 punctate, with a subcentral mucro, which is studded with minute 

 eyes, posterior slope slightly concave. Girdle, with characteristic 

 minute elongated glossy scales. Colour fleshy, lighter and with white 

 streaks on the jugum ; a white squarish spot on each intermediate 

 valve on the posterior part of the jugum, and on the tail valve in front 



