Mestayek. — New Zealand Mollusca. 177 



Girdle moderately broad, with a marginal fringe of soft short bristles, 

 and about twenty tufts and pores adjoining the valves ; when alive it was 

 a greenish colour. 



Measurements : Length, 35 mm. ; breadth, 20 mm. ; but it would pro- 

 bably have been at least 5 mm. longer and broader in life. 



Material : The holotype, in the Dominion Museum. 



Remark*. — This specimen was obtained accidentally when gathering 

 Ulva-co\ered pieces of rock ; a tuft came away readily, and I found it 

 was on this chiton, which it had completely hidden. Having no idea 

 is was a new species, it was not mpasured while alive, nor was the radula 

 preserved. In spite of repeated searches in the same place, no further 

 specimens have been obtained. It belongs to the group of Plaxiphora 

 which has been placed by Iredale in the subgenus Maorichiton., with 

 Chiton caelata Reeve as the type. 



ISCHNOCHITONIDAE. 



Lorica H. and A. Adams (2). 

 Lorica haurakiensis n. sp. (Plate XXXVIII, figs. 1-3.) 

 Lorica volvox Suter (non Reeve) (3). 



Off Kawau Island, Hauraki Gulf, N.Z. ; 20 fathoms. 



Shell ovately oblong, steeply elevated, dorsal ridge acute, side slopes 

 very slightly convex. Anterior valve erect, lightly curved forward, with 

 fourteen irregularly spaced radial ribs, smooth for about two-thirds theij 

 length, but bearing near the girdle from four to six low, steeply rounded 

 nodules ; the interstices show faint concentric growth-lines ; posterior 

 angles of the apex finely vertically ribbed. Median valves : The first of 

 these is considerably larger than the others the jugal area sculptured 

 with oblique radial ribs which form inverted "V" up it (Plate XXXVIII, 

 fig. 3) ; pleural areas finely horizontally ribbed. In valves 3 to 8 the hori- 

 zontal ribbing is continued across the jugal tract. The number of ribs varies 

 with the age of the shell ; the holotype has nineteen horizontal ribs, the 

 interstices rather wider and perfectly smooth. The lateral areas raised, 

 somewhat variable, some having two or three more-or-less-decided radial 

 riblets, but they may be obsolete on one or more of these areas. A few 

 low, steeply rounded nodules are rather irregularly scattered over the 

 riblets. Posterior edges of valves denticulate, and showing traces of fine 

 vertical striae at the apex. The concentric growth-lines are clearly visible. 

 Posterior valve the smallest, horizontally ribbed, bounded by a strong 

 slightly upstanding rib, bearing a few nodules. In some specimens there 

 are traces of fine vertical riblets on the posterior angle. The mucro is 

 terminal. The valve rather deeply grooved posteriorly. 



Girdle medium width, closely set with smooth convex scales, which vary 

 slightly in size. There are no tufts of bristles ; the posterior slit extends 

 the whole width of the girdle. Unfortunately this is not shown in fig. 1. 



Colour reddish-brown with a fairly broad creamy-yellow bar along the 

 centre of the shell. The girdle about the same colour, with darker trans- 

 verse bars. Individual specimens appear to vary somewhat in colour. 

 Interior reddish, sutural plates almost white, sinus very narrow, rather 

 shallow. Anterior valve with about eight slits, median valves one slit. 

 Owing to the scarcity of specimens it has not been possible to disarticulate 

 one. 



