240 LIOLOPHURA. 



colored, having anterior and side insertion-plates slit into teeth and 

 sharply pectinated outside ; posterior valve with posterior terminal 

 mucro, lacking the insertion-plate, which is represented by a flat 

 callous ledge. Sinus wide,, deep, smooth. 



Girdle covered with stout calcareous spines or obtuse club-shaped 

 processes. Type Chiton japonicus Lischke. 



The species of this genus have been referred to Acanthoplewra, 

 Maugeria and Chiton by authors who have mentioned them ; but 

 from these groups the characters of the tail-valve at once sunder 

 them. Liolophura resembles Onithochiton and Enoplochiion in hav- 

 ing a callous ridge in place of the posterior insertion-plate, in the 

 pectinated teeth of the other valves, and in the possession of eyes ; 

 but it differs from Onithochiton (a) in the somewhat raised instead of 

 marginal mucro, (b) in the dullness of the valves externally, (c) in 

 the distribution of the eyes upon the sides of the central ureas, whilst 

 in Onithochiton they occupy a band on the forward part of the lateral 

 areas only; and finally (d) in the covering of the girdle which in 

 Liolophura consists of densely crowded calcareous spines, comparable 

 to the spines of Maugeria. Liolophura differs from Enoplochiton in 

 lacking the interior sculpture and denticulate sinus characteristic of 

 that genus, and in the totally diverse development of the girdle 

 covering. 



L. GAIMARDI Blainville. PL 53, figs. 30-35. 



Shell oblong, depressed, roundly arched. Surface lusterless, buff- 

 gray, marked at sides and on ridge of valves with black. Girdle 

 tessellated light and dark, having a light bar opposite each suture, 

 or having dark or light larger patches. 



The valves are somewhat beaked, but always considerably eroded ; 

 lateral areas but little raised, concentrically wrinkled toward their 

 bases, studded with minute scattered eyes appearing as black dots. 

 Central areas wrinkled by lines of growth and having scattered eyes 

 at the sides. Head valve concentrically wrinkled, studded with 

 eyes. Tail valve small, depressed, similar in contour to the median 

 valves, the mucro being posterior and terminal, but eroded. 



Interior dark red-brown, whitish on the edges of the sutural-plates 

 and the valve-callus; posterior internal margin covered by the 

 reflexed blackish-brown tegmentum. Sutural-plates brownish below 

 with a white outer edge ; seen from above they are whitish shading 

 into reddish-brown toward the median sinus; rounded, broadly 

 separated by a very wide, deep, rounded sinus. Anterior valve hav- 



