ACANTHOCHITES-CRYPTOCONCHUS. 37 



bunches of short bristles, situated near the sutures upon the sides of 

 the valves, and four around the head valve. 



Length 34, breadth 14 mill, (dried specimen.) 



Length 38, breadth 20 mill. ( Q. & G.) 



Dunedin to Auckland, New Zealand. 



Chiton porosus BURROW, Elements of Conchology, p. 189, t. 28, 

 f. 1 (1815). Cryptoconchus porosus H. & A. AD., Gen. Rec. Moll, 

 iii, t. 55, f. 4. CHENU, Manuel, i, f. 2884. HUTTON, Man. N. Z. 

 Moll., p. 118 (1880). Chiton monticularis QUOY & GAIMARD, Voy. 

 de 1'Astrol., p. 406, t. 73, f. 30-35, (1834). SOWB., Conch. 

 Illustr., f. 129. REEVE, Conch. Icon., t. 10, f. 57. Chiton leachi 

 BLAINVILLE, Diet. Sc. Nat. xxxvi, p. 554 (1825). ? Cryptoplax 

 depressus BLAINV., I. c., vol. xii, p. 124 (1818). ? Cryptoconchus 

 stewartia?ius ROCHEBR., Bull. Soc. Philomath. Paris, 1881-1882, 

 p. 194. 



The girdle varies from bright orange to light brown in the living 

 animal (figs. 57, 58). The gills are posterior. 



A. FLORIDANUS Dall. PL 3, figs. 63, 64. 



Elongated and narrow ; black, purple-black or light brown, with 

 a linear white space along the summit of each valve. 



Valves entirely covered except a round dot at the apex of the first, 

 and a narrow band along the ridge of the other seven, the band slightly 

 dilated at the apex of each valve. These exposed portions are whit- 

 ish or purplish, smooth or showing faint transverse growth striae. 

 The posterior edges of each valve, seen through the dried skin, are 

 produced backward in wide but not deep rounded lobes on each side 

 of the apex. Posterior valve with subcentral mucro. 



The disconnected valves are white or pink and purple ; the inter- 

 mediate valves being rectangular in general shape, with a sinus 

 before and behind, the posterior sutural lobes rather narrower than 

 the anterior ; and there is one slit on each side. The posterior valve 

 has a gentle wide upward wave posteriorly, with a single Mopaloid 

 slit on each side, and several (4) unequal slits between them. Ante- 

 rior valve having 5 slits. 



Girdle rather wide, leathery, naked ; when fresh having the color 

 and "texture of a moist prime" ; bearing at each suture a minute 

 bristle-pore, and four such pores around the head valve ; each pore 

 bearing some short bristles, scarcely projecting above the surface ; 

 pores and bristles always inconspicuous, frequently invisible 

 (aborted?). 



