IREDALE : THE CHITONS OF THK KKRMADEC ISLANDS. 27 



was the extniordinarv tuil-valve. He referred the species to the 

 genus Lepidopleurns, mainly on account of the lack of insertion- 

 plates. 1 liad already concluded that the genus Lepidopleurus was 

 polyphyletic, and now anticipate its dismemberment as material 

 becomes available. I had determined to remove the following species 

 from Lepidopleurus before I recognized that it was certainly 

 a second member of Thiele's sub-genus Parachiton. That fact at once 

 compelled me to advocate the recognition of Thiele's sub-genus as 

 worthy of full generic rank, and its inclusion in the family Lepido- 

 pleuridte is simply due to the fact that insertion-plates are absent. 

 I believe that the division of the Polyphicophora into the sub-orders 

 Lepidopleurina and Chitouina is artificial, and that further study will 

 lead to the disintegration of the former and the transference of the 

 present members of it to various families of the Chitonina. 



Parachiton mkstaykr.e, n.sp. PI. I, Fig. 1. 



Shell elongate, faintly keeled, elevated, side-slopes slightlj- convex, 

 laat valve disproportionafeh/ larffe, girdle spiculose. General coloration 

 pink, slashed with longitudinal white streaks. Anterior valve 

 regularly quiiicuncially punctate. Median valves narrow, not beaked, 

 first very slightly larger than the others; lateral areas little raised, 

 the sculpture regular (|uincuncial punctation ; the pleural areas are 

 closely longitudinally striate, the striation becoming finer as it 

 approaches the dorsal ridge, where, however, it still persists. Posterior 

 valve much larger than the anterior valve; the mucro elevated at 

 about the posterior fourth, the posterior area being concave. The 

 anterior portion is triangular, its length twice as long as the pre- 

 ceding valve ; it is similarly sculptured to the pleural areas of the 

 median valves, whilst the posterior area is regularly quincuncially 

 punctate, the punctation showing clearly on account of tlie protection 

 afforded by the concavity of this area. Inside coloration pinkish- 

 white. Insertion-plates absent. The sutural laminae snuiU, irregularlv 

 quadrangalar, and very far apart. The girdle, owing to the difficulty 

 of preserving, appears somewhat imperfectly covered with very 

 slender elongate needles, with a fringe of much longer silvery 

 spicules. 



A minute curled juvenile specimen shows the same sculpture as 

 the adult; the (juincuncial punctation appears more prominently, and 

 the longitudinal striae more pronounced. Length of type 11, breadth 

 6 mm. A much larger specimen curled up before it could he preserved. 



Hah. — Sunday Island, Kermadec Group. 



Station. — Dredged oft' the north coast on gravelly bottom in 

 15 fathoms; also in Denham Bay in 25 fathoms. "From 15 to 25 

 fathoms was dredged a fine Lepidopleurus, which has no near relation 

 yet on record. It faintly resembles some Japanese species." 



Remarks. — This is undoubtedly most nearly allied to Lepidopleurus 

 acuminatus, Thiele, but otherwise no other shell is comparable. 

 L. acutnittatiis, Thiele, has the apex of the posterior valve moi-e 

 posterior, and consequently the posterior area more diminished. 



