204 TONICIA. 



Tonicia lebnuii ROCH., Bull. Soc. Philomath. Paris, 1883-'84, p. 

 35 ; Polyplac. Cap Horn, p. 138, t. 9, f. 6. 



T. FONTAINE: Rochebrune. Uw figured. 



Shell ovate, broad, subcarinated, gray, with brown spots. Ante- 

 rior valve, lateral areas of intermediate valves, and posterior part of 

 posterior valve very delicately striatulate and sparsely covered with 

 conic tubercles ; central areas sculptured with beaded longitudinal 

 waved lines. Marginal ligament rather wide, leathery, rufous. 



Length 11, breadth 9 mill. (Rochebr.} 



Chili (M. Fontaine) ; Paris Museum. 



Tonicia fontainei ROCHEBR., Bull. Soc. Philom. de Paris, 1881- 

 1882, p. 193. 



The foregoing species are not defined with sufficient exactness to 

 insure their indentification, Rochebrune being a century behind the 

 times in 'descriptive zoology. 



T. ARGYROSTICTA Philippi. Unfigured. 



Girdle smooth. Valves smooth, subcarinated ; lateral areas hav- 

 ing a single series of distinct silvery impressed dots. 



Length 4, breadth 3 lines. 



This small species is sufficiently distinguished by the peculiar 

 impressed silvery-shining points, which remind one of the similar 

 marking on some Carabidse. On both end valves they stand in 

 several concentric rows. The coloring varies ; the brown-red color 

 predominating; in one example there are whitish flecks and trans- 

 verse stripes, in another longitudinal stripes. (P/w7.) 



Straits of Magellan. 



Chiton argyrostictus PHIL., Archiv fiir Naturg. 1845, p. 59. 



T. ZSCHAUI Pfeffer. PI. 40, fig. 12. 



The animal is much elongated, the breadth hardly one-half the 

 length. The inner region of the girdle is covered with very minute 

 granules, hardly visible under a strong lens, arranged in not entirely 

 regular oblique series, and separated by about their own dimensions. 

 Under a low-power lens the girdle appears quite naked. Toward 

 the margin these granules grow into transparent, short spines. The 

 28 branchiae reach the entire length of the foot. 



The valves are quite shining, and sculptured with close growth- 

 strive ; otherwise they appear smooth under a weak power of the 

 lens ; under strong magnification a fine granulation is visible. The 

 median valves have only a low angle separating central and lateral 



