ortmann: south American naiades. 587 



It is also remarkable for the yellowish browii color of the epidermis, but this may 

 be variable. In the relative dimensions it comes near M. lentiformis (height and 

 diameter), and it is also a decidedly flat shell, although the beaks are slightly more 

 inflated than in lentifonnis. The compression of the anterior extremity also should 

 be noted. 



I name this species in honor of Dr. W. J. Hofland, Director of the Carnegie 

 Museum, under whose auspices the expedition to Central South America by Mr. 

 John D. Hascman was made. 



Anatomy. — The specimen at hand is a male. 



Soft parts like those of the foregoing species, but the following points should 

 be mentioned : the inner edge of the anal opening is practically smooth, that of the 

 branchial opening with very minute papillae, which appear as mere crenulations; 

 the gills have solid septa, which are unequal in thickness, heavier and hghter 

 ones alternating in a more or less regular way, chiefly so in the middle of the gills. 



Genus Anoduntites Bruguiere (1792). 



Anodontites Bruguiere, Journ. Hist. Nat., Paris I, 1792, p. 131; Pilsbry, 1911, p. 



609; Ortmann, 1911c, p. 91; Simpson, 1914, p. 1403. 

 Patularia Swainson, Malacology, 1840, p. 287, 381. 

 Glabaris Gray (1847) Simpson, 1900, p. 916. 



In this genus the hinge is without any teeth. From Mycetopoda and Leila it 

 differs by the absence of the characters peculiar to these, i.e., in the shape of the 

 shell, and certain features of the soft parts (See key p. 568). Furthermore we 

 find in Anodontites an extreme variability in the shape of the shell, from rounded 

 and subovate, to subtrapezoidal and elongated. The number of species is very 

 great, and it is hard to arrange them. Simpson (1914) distinguishes three sections. 



1. Section Anodontites (sensu slricto). Shell rounded to elliptical; posterior 

 ridge low or wanting. 



2. Section Stycjanodon Von Martens (1900). Shell subrhomboidal, with a 

 thick, dark, rather rough, sombre-colored epidermis, which is sometimes faintly 

 rayed; nacre lurid, shaded green. 



3. Section Virgula Simpson (1900). Shell subsolid to solid, moderately in- 

 flated, greatly elongated, straight or falcate, roundcnl in front, sharply pointed 

 at the posterior base, where the high, sharply defined posterior ridge ends, and 

 above which it is somewhat obliciuely truncated; beaks not high; epidermis green 

 to olive; nacre brilliant, blueish or purplish, iridescent, rayed with very fine, in- 

 distinct ridges; posterior end with a slight sinus. 



