' BYFTOPLAX. 



FBIAIUa Lamarck. PL 9, figt, 11, 12,13,11, t5j J.I. 11, figg. 



Elongated, vermiform, very >>- e x above, flat below; hoary- 

 maculated with rast-broWD; when dry, dull reddish-brown. ' 77,", 

 Mfofl arfl HI contact with one another, or the posterior four may !. 

 separated by short intervals, always much shorter than the valves. 



Anterior valve having the tegmentum longer than wide, more than 



twice as long as the anterior teeth ; its surface cut into a coarse 



irregular granulation by peculiar zigzag impressions [very badly 



rendered in pi. 9, fig. 11]. Median valves (fig. 13) sagittate, widest 



^ about the posterior third, tapering forward ; sculptured with 



several deep, finely and irregularly zigzag grooves at the sides 



lometimes transformed into a pattern of v-shaped granules) the 



dorsal area narrow, raised, smooth except for slight growth lines 



Posterior valve (fig. 14) like the median valves externally but 



having a short vertical granulose slope below the mucro. 



Interior light olive-green, generally becoming pink on the sutural- 

 iroinse and teeth. Anterior valve having 3 slits, other valves 

 none; posterior valve having the insertion-plate continuous, but 

 somewhat emarginate behind. 



Girdle wide, fleshy, densely covered with minute calcareous spine- 

 Jts, and in most good specimens showing minute pores at some or 

 all of the sutures, and four around the head-valve. 

 Length 55, breadth 12 mill, (average dry specimen.) 

 Length 61, breadth 22 mill, (alcoholic specimen.) 

 Chitonellus striatus LAM., An. s. Vert, vi, p. 317, 1819 DESK in 

 Lam. vii, p. 481, 1836. SOWB., Genera of Shells 1. 139, f. 4; Conch 

 [llustr., f. 62. BLAINV., Diet. Sc. Nat. xxxvi, p. 551 1825 

 Ki i VE, Conch. Syst. ii, t. 135, f. 1 ; Conch. Icon., f. 4. Chitonellu* 

 ffunnn RVE, Conch. Icon., f. 5, 1847. Ch. rostratus RVE. / e f . 6 

 Ch. oculatoB RVE., 1. Cl , f. 7a, b (not of Q. & G.).- Cryptoplax stnata 

 -i-yunni+rostrata H. & A. ADAMS, Gen. Rec. Moll, i, p 484 

 Ax<;AS,P.Z.S. 1867, p. 224, 225,-C/^ (Chitonellus) striatns 

 SMITH, Zool. Coll. 'Alert/ p. 84.- Cryptoplax striatus HADI 

 t'liiill. Hop. xv, p. 39, t. 1, f. 9; t. 3, f. 9a-9m. 



Raines Island, Torres Straits (Reeve, for C. rostratus and C 

 Tiatus), Port Lincoln (J. B. Harvey), Newcastle (Dr. Dieffenbach), 

 Port Jackson (Coppinger, Richardson, Jukes, Kinr), 

 M>u,,l _(.!. Milligan); Tamanfa (Reeve, C. gunnii) ; T 

 (Macgillivray and Gunn). 



