THE NAUTILUS. 



of the gill. The ova form distinct, subcylindrical placentae. 

 The glochidia are subelliptical, nearly semielliptical, about as 

 high as long, L. and H. 0.16 rnm. They are much like those 

 of F. flava, but slightly larger. 



Color of soft parts of the orange type, chiefly evident on the 

 foot, mantle-margin, and adductor muscles. However, this 

 color is not very intense, often very pale orange, and in young 

 specimens the soft parts are sometimes whitish. The gonads 

 are red, and so are the eggs and placentae, from pink to bright 

 crimson; in some cases they are pinkish-orange. 



This group undoubtedly represents, in the upper Tennessee, 

 the/am-group of the interior basin. 



FUSCONAIA EDGARIANA (LEA), F. EDGARIANA ANALOGA (ORTM. ). 



(See: F. cor and cor analoga, Ortmann, 1. c. , pp. 532-533). 



Most of the specimens preserved in alcohol represent the flat 

 headwaters-form (analoga), but I have a sterile female (Ander- 

 son Co., Tenn.), which is the swollen typical form. 



Gravid females : May 13, 14, '13; July 5, 7, 8, '13. Of those 

 preserved none happened to have glochidia. 



Soft parts identical with those of F. cuneolus, and with those 

 of the^Zaua-group in general. Color in most cases deep orange, 

 chiefly so foot and adductors. I never found specimens with 

 whitish soft parts, and only a few are marked: pale orange. 

 Gonads, eggs and placentae rarely pink, mostly intensely 

 crimson. 



FUSCONAIA BARNESIANA (LEA) and varieties. (See: 1 c. , p. 



534 ff.). 



The anatomy of this group has been described previously. 



(See: NAUTIL. 31. '17, pp. 61, 62.) 



LEXINGTONIA DOLABELLOIDES (LEA), L. DOLABELLOIDES CONRADI 



(VANATTA). (See: 1. c., pp. 545, 546.) 



Gravid females : May 11, 13, '13; July 5, 7, 9, 10, 13, '13. 

 Glochidia: May 13 and July 5 (tachytictic). 



All gravid specimens belong to the compressed headwaters- 

 form (conradi), but I have examined the soft part of males and 



