NO. 2164. REVISION OF ROTATORIAN GENERA— HARRINO. 561 



plate is slightly convex and has an extremely high and very thin 

 median keel, extending the entire length of the lorica. The ventral 

 plate is almost plane. The cross section of the body is triradiate; 

 the lateral portions of the body and the keel are very thin, about 

 one-sixth the width of the lorica. The dorso-ventral depth of the 

 body from the highest point of the keel to the ventral plate is a 

 little more than one-half the length of the lorica. 



The width of the anterior margin is about two-fifths of the length 

 of the body. No dorsal sinus is present; the frontal edge of the 

 dorsal plate has a shallow notch between two slightly convex lobes. 

 The ventral sinus is broadly V-shaped and rounded posteriorly. 

 There is no stippled collar or any beadlike reenforcement of the 

 anterior edge. 



The foot groove is slightly ovate and about one-third of the length 

 of the lorica; its width is a little more than half the length. The 

 posterior end of the lorica projects as an inconspicuous, obtusely 

 pointed lobe, as wide as the dorsal keel. 



The foot is a little less than one-third the length of the lorica and 

 moderately stout; its three joints are of nearly equal length. The 

 toes are slender and slightly decurved; their length is about one- 

 fourth of the length of the body. 



Total length, 100 ju (small specimens, 83 ^u) ; length of lorica 75 /x, 

 width 64 fi ; anterior margin, 30 n; depth of median dorsal notch, 3 fx, 

 of ventral sinus, 14 /x; length of foot groove, 25/i, width, 15 fx; length 

 of foot, 23 ju; length of toes, 20 ix; depth of body, 40 fi. 



Lepadella iriptera is widely distributed; as it is so small and diffi- 

 cult to find, it is probably more abundant than the published records 

 indicate. 



Genus LOPHOCHARIS Ehrenberg. 



Lophocharis Ehrenberg, Infusionsth., 1838, p. 458. Tj^e (Monotype), Lopho. 



charis salpina {'Eh.renh&cg)=Lepadella salpina Ehrenberg. 

 Oxysterna Iroso, Mon. Zool. Italiano, vol. 21, 1910, p. 303. Type (by original 



designation), Oxysterna oxysternum {Go^e)= Metopidia oxysternon Gosse. 



As noted in the introduction, the two species included in this genus 

 have usually been referred to Lepadella ( = Metopidia) . There is no 

 justification for this, as the genus is a well-marked one and differs 

 in many important characters from the Lepadellids. 



The lorica is a very rigid, boxlike structure protecting the body 

 on all sides. It is somewhat rhomboid in cross section and has a 

 prominent dorsal keel, of a height equal to about one-tliird the dorso- 

 ventral depth of the body, extending the entire length of the lorica. 

 A prominent lateral ridge bifurcates anteriorly and continues to the 

 posterior end of the lorica, curving slightly upward in the region of 

 -ProcN.M.vol .fil— 16 36 



