ARCULARIA. 25 



A r . circumcincta, A. Ad. (tig. 17), is founded on specimens 

 showing the onmge-bordered callus. It was erroneously reported 

 from the lied Sea, but has been found at Alexandria and on the 

 Syrian Const. 



X. KRAUSSIANA, Dunker. PI. '7, figs. 18, 19. 



Yellowish brown, indistinctly dark banded ; callus yellowish 

 or orange. Length, '4-'5 inch. 



South. Africa. 

 N. orbiculata, A. Ad. (fig. 19), is identical. 



X. THKRSITKS. Brug. PL 7, figs. 20-23. 



Ash, yellowish or brown, sometimes mottled, with usually a 

 light central band. Ribs usually obsolete on the mouth side of 

 dorsal hump. Length, -6--85 inch. 



Indian Ocean, Hong Kong, Manilla, Australia. 



N. bimaculoxa, A. Ad. (fig. 22), represents a stumpy specimen 

 of this species. It was described as from the Philippine Islands, 

 and Mr. E. A. Smith reports it from Andaman Islands, " sand- 

 banks, at k)w tide; very active animal." N. dorstuma, A. Ad. 

 (fig. 23), from Philippines, is evidently a monstrosity ; besides, 

 the shell looks as if it had been roasted : it is probably a 

 synonym. 



X. LEPTospiRA, A. Ad. PI. 7, figs. 24-28. 



Yellowish ash-color, longitudinally rather closely plicated ; 

 callus yellowish, wide spread. Length, '75 inch. 



llo Ilo, Isle of Panay, Philippine* (on mud banks, at low 



water, Turning); Japan; Ascension InL (Pease*. 



This may be considered on the one hand as a less-developed 

 form of N, The,rsit?.$,im the other as connected with N.foveolata, 

 N. /lYvwo/x, etc., in which the sculpture and general appearance 

 are similar, but the callus is not spreading. I unite with it N. 

 graci'liti, Pease (tig. 25), N. btlliila, A. Ad. (tig. 26), N. labida, 

 Reeve (fig. 27 ), and X. /Vr.sav/ . Martens (fig. 28). N. Deshayvsiana, 

 Issel, has been considered the equivalent of N. Perxica, von 

 Martens, by several excellent conchologists : very probably it is 

 so, but it is tuberculate, shouldered, without spreading cnllus, 

 and typically is no. closer to A r . Perxica than are most of the 

 nodulous species. 

 4 



