326 PLAXIPHORA. 



elevated, subtriangular. uniform and smooth except toward the 

 anterior margins where they are marked with three or four mar- 

 ginal striae ; they are black toward the lateral margins, with a tri- 

 angle of the same color in the middle, bordered with yellowish or 

 greenish. 



Inside they are of a beautiful emerald green, the sutural laminae 

 being of the same color and separated by a wide sinus. The anterior 

 valve has its margin cut into 9 smooth teeth. Posterior valve hav- 

 ing a semi-circular ridge in place of the teeth. The valves taken 

 together form an elongated oval. All of the intermediate valves 

 have one slit and- two transverse striae on the apophyses. 



Girdle of a beautiful light green, covered with rigid but not acute 

 bristles of the same color. (Q. & 6r.) 



Length 50, breadth 37 mill. 



cV Entrecasteaux Channel, Tasmania. 



Chiton glaucns Q. & G., Voy. de PAstrol. Zool. iii, p. 376, t. 74, 

 f. 7-11 (1834). Not Chiton glaucus GRAY, an undetermined species, 

 see p. 172.^Plaxiphora ciliata ANGAS, P. Z. S. 1865, p. 187, not 

 Chiton ciliatus SOWB. 



This species is evidently allied to P. petholata. It is probably the 

 form Angas collected at Guichen Bay, South Australia, and listed 

 as " P. ciliata" He found it on rocks at low water, and remarks 

 that it is the largest of the South-Australian Chitonidse. 



Group of P. terminalis. 



Sculpture stronger than in P. petholata. Girdle generally with 

 more or less distinct sutural pores. Distribution, New Zealand. 



P. TERMINALIS (Cpr.) Smith. PI. 51, fig. 14. 



Shell resembling P. petholata in sculpture, but more elevated, 

 longer, the mucro entirely terminal, produced. Dorsal ridge striped 

 with white. Sculpture much more distinct, consisting of irregularly 

 zigzag wrinkles all over, coarser at the sides. 



Interior having 8 slits in the anterior, 1 in the median valves. 

 Posterior valve with subplanate insertion plate ; the subjugal area 

 punctate, teeth, sinus and eaves as in P. petholata. Girdle having 

 bunches of long horny hairs at the sutures and around the margin, 

 elsewhere smoother. 



Length 25, breadth 12i mill. ; divergence 120. (Cpr.} 



New Zealand (Cuming.) 



