1922] NATURAL SCIENCES OF PHILADELPHIA. 41 



were absent from the ancient Atlantic or Antarctic continents, or, 

 if present, have left no modern descendants. 



Genus HENDERSONIA A. J. W. United States, China, Japan. 

 Apiopomatinae A. J. Wagner (1905). No possible type genus. 



Section Hendersonia s. s. United States 



Hendersonia A. J. Wagner (1905). Type (monotype) Helicina occulta Say 



(1831). Subfossil, New Harmony, Indiana. 

 H. occulta (Say) (1831). Subfossil, New Harmony, Indiana. (North-eastern 



U. S.). H. rubella Green (1832). Alleghany County, Pa., U. S. (living 



or fresh). 



Section Miluna A. J, W. S. China. 



Miluna A. J. W. (1905). Type (monotype) M. josefinae A. J. W. (1905); 

 Radung-Hubei. 



Section Waldemaria A. J. W. Japan. 



Waldemana A. J. W. (1905). Type H. japonica A. Adams (1861). Japan. 



In this genus the radulae of H. occulta (Say) 1 and H. japonica 

 (Adams) 2 were examined. The formulae are shown in Table II. 

 In this table, under the headings "A, B and C Centrals" (the 

 R-centrals are omitted as they usually have no true cusps) are 

 given the number of cusps on each tooth for. the various species. 

 Under the heading "Comb-lateral" are given the number of cusps 

 on that tooth. Under the heading " Marginals, " the subheadings 

 "2, 3, 4, 5, 6" indicate numbers of cusps; under each of these 

 subheadings is given the number of teeth that bear the complement 

 of cusps indicated. Where the inner teeth bear more cusps than 

 some further out; these interstitial few-cusped teeth are put in their 

 proper column but are marked with an asterisk, while the two 

 groups of teeth with one more cusp, situated on either side of them, 

 are put in their proper column but the first and second groups are 

 separated by a plus sign. For instance, A. verecunda has 4 cusps 

 on the inner most marginal (1 in 4-column), followed by 2 teeth 

 with 3 cusps each (2 followed by an asterisk in 3-column), which 

 in turn are followed by 3 more teeth with 4 cusps (+ 4 in 4-column). 

 Under the heading "Total" are given the number of marginals on 

 each side; under "Grand Total" are given the usual number of 

 teeth in each transverse row. 



In H. occulta, the R-central (Plate III, fig. 1) is peculiarly attenu- 



*5 dried specimens; A. N. S. P. no. 10593; collected at Iowa City, Iowa, by 

 B. Shimek (1891), and H. A. Pilsbry (1882). 



2 2 dried specimens; A. N. S. P. no. 84383; collected at Sotokaifui, Sado. 

 Japan, by Y. Hirase (1902). 



