s 
Pore SR woe wrong 
HS Te 
1918.] NATURAL SCIENCES OF PHILADELPHIA. 317 
The head and back are blackish brown, fading downward and back- 
~ward to dark grayish brown, the tail paler. The sole has lateral 
bands somewhat darker than the central field (No. 119,048). 
Genitalia (fig. 11) generally similar to S. hachitana. The penis 
is very slender, its retractor muscle longer; penis-papilla slender, 
smooth, with tapering end. A short flagellum is present. The 
epiphallus is nearly as long as the penis. The vagina is generally 
longer than the penis. 
In one specimen dissected, Station 20 (fig. 12a), the penis is about 
a third longer, its papilla very long, three times the usual length or 
more. The flagellum also is much longer. Such differences would 
usually be thought specific, yet I have not found any differences in 
the shells from this locality. 
Fig. 12. a, Genitalia of S. cerulifluminis var., 119,047, from Station 20, 
Blue River. b, S. binneyi franciscana Ne. 119,044. ¢ 
Measurements of genitalia of S. cerulifluminis. 
Collecting Station.... 18 19 16 20 
TEES Ts A pe age ee oa 8.5 7.5 7 12 
Penis-papilla....... 3 3.9 + 11 
Epiphallus......... 8 Gr 7 8.7 
Hiawelinm 300.22 2. Oi Oe 0.5 2 
WPeRACLOD. 0... aiec1. 5,0 on es. 10 13 
Vite a ene 15 14 8 9.5 
Museum No...... + 119,048 119,042 119,046 119,047 
