1466 MYCKTOPODA 



row and broadens out only towards the hinder end, where it 

 becomes 3 mm. wide. Nacre blue and red, iridescent, except 

 under the hin^e where it is a yellowish-brown. 



Length 85. heiglit 23 mm. or 29/100 of the length." (von 

 Ihering). 



Type locality, Rio Arag'ua}a, Ilha do Bananal. 

 Mycetohoda kransci von Iheri-NG, Abh. Senck. Ges., XXXII, 



I9IO, p. I2T, pi. 12, fig-. 2a-b. 



Group of Mycetopoda I'cntricosa. 



Shell rather short and high, subrhomboid with a strong an- 

 gle at the anterior upper point, cut away below in front, 

 slightly sinuous on the base, narrower behind ; strongly trun- 

 cate on posterior slope ; posterior ridge wide and lightly 

 curved ; hinge line curved. 



Mycetopoda vkntricosa d'Orbigny. 



Shell somewhat elongated, rhomboid, thin, subinflated, yel- 

 lowish-brown, very inequilateral ; beaks somewhat elevated ; 

 dorsal and ventral lines nearly straight and parallel, the latter 

 slightly incurved ; anterior end angled above, rounded and cut 

 away below ; posterior end obliquely truncate above, bluntly 

 pointed below the median line, rounded below ; nacre flesh- 

 colored. 



Length 112, height 42, diam. 21 mm. 



Bolivia. 

 Mycetopoda ventricosa d'ORincNY, Voy. Am. Men, 1843, P- 



602, pi. Lxxii, figs. 1-3. — SowERBY, Conch. Icon., XVI, 1868, 



pi. Ill, fig. 8. — Clessin, Conch. Cab. Ano., 1875, p. 202, pi. 



Lxix. figs. 2, 3. — Simpson, Syn., 1900, p. 935. 

 Platiris (Mycetopus) ventricosus Lea, Syn., 1852, p. 56; 1870, 



p. cp. 



This differs from the other species in being very inequilat- 

 eral. The dorsal and ventral outlines are nearly straight and 

 parallel ; the general outline is decidedly rhon^boid. 



