MYCETOPODA 1 465 



nacreous, marked throughout with very fine, radiating, punc- 

 tate striae. 



Length 72. height 21.5 mm." (Preston). 



Type locaHty. Rio Chenchi, U. S. Colombia. 

 Mycetopiis pnnctatus Prrston, Ann. Mag. Nat. Hist., (8), III, 



1909, p. 513, pi. X, fig. 8. 



Mycetopoda punctata von Ihering, Abh. Senck. Ges., XXXII, 



1910, p. 122. 



Von Ihering, (1. c. ). remarks: "This species stands very 

 close to M . kraiisei, but differs from it by the more anteriorly 

 situated and less inflated beaks, which do not rise above the 

 dorsal margin, while in krausei the elevation is conspicuous. 

 The punctate, radial striae on the interior of the shell, which, 

 according to Preston, characterize the species, are not visible 

 in M. krausei.'' 



Mycktopoda krausei von Ihering. 



"Shell thin, moderately large, quite elongate, gaping rather 

 widely in the anterior half. The greatest diameter is about 

 in the middle of the shell, from which it slopes gradually to 

 the posterior margin, and anteriorly as far as the beaks, from 

 which point it slopes more rapidly to the anterior margin. 

 The beaks are flat, small, slightly prominent and are situated 

 at 21 mm. from the anterior end. being 1-4 of the length. An- 

 terior end regularly rounded ; the hinder end tongue-shaped, 

 pointed, with the point below the middle of the shell. The 

 dorsal margin is straight and meets the anterior margin at a 

 sharp angle ; the ventral margin is curved, oblique in front and 

 extending posteriorly to the height of the sinulus, whence it 

 gradually ascends to the hinder end. An obtuse, broad ridge 

 extends from the beaks towards the hinder end. Above this 

 two or three shallov/ furrows extend posteriorly. Epidermis 

 bright olive-green, becoming brownish towards the ventral 

 margin, with feeble, radiating rays. Muscular impressions 

 weak, the posterior adductor "scars extend anteriorly to the 

 middle of the sinulus or even a little further. The sinulus is 

 small, not deep and triangular. The prismatic border is nar- 



