1911.] NATURAL SCIENCES OF PHILADELPHIA. 485 



Mesomphix inornata (Say). 



Cf. Bland, Ann. Lye. N. H. of N. Y. ; VII, 127. 



Genitalia as in M. rugeli. Caudal pore as in 0. cuprea. 



The radula (PL XXXIX, fig. 5) has 24, 1, 24 teeth. The tricuspid 

 centrals have an hour-glass-shaped basal-plate and well-developed 

 cusps. There are two lateral teeth, the next two teeth being tran- 

 sitional. Three side teeth have cutting points on the ectocones. 

 The marginal teeth are less crowded than in M. subplana or M . 

 andrewscc, with shorter cusps than the former. 



The number of teeth in a row is much smaller in M. inornata 

 than in any species except M. laevigata. The cusps of the lateral 

 teeth have a bulging outline on the inner side as in M. andrewsce, but 

 they are much longer than in that species. 

 Mesomphix andrewsae (Pils.)- 



The tail pore is like that of M. laevigata. The mantle is not pig- 

 mented over the lung. The genital system (PL XXXVII, fig. 11) 

 differs from related forms by the greater length of the spermatheca 

 duct and epiphallus. The penis is strongly swollen near the base 

 and has a rather long terminal gland (p.g.). Its retractor muscle 

 is long. The very short vagina is somewhat swollen near the base, 

 but I can see no vaginal gland there. Length of penis 3.5; of 

 epiphallus 14 mm.; of spermatheca and duct 9.5 mm. 



The radula (PI. XXXIX, fig. 4) has 40, 1, 40 teeth, more crowded 

 than in M. inornata, the central and lateral teeth have much shorter, 

 stouter cusps. There are three lateral teeth, the next two being 

 transitional. The marginal teeth are less slender and graceful than 

 in M. inornata. 



The radula of M. andrewsce most resembles that of M. inornata, 

 but differs by the much shorter cusps and the far greater number 

 of teeth. 



The soft anatomy of M . a. montivaga Pils. has not been examined. 



Explanation of Plates XXXVII, XXXVIII and XXXIX. 



Plate XXXVII. — Genitalia of Omphalina and Mesomphix. 



Fig. 1. — Omphalina kopnodes (\V. G. B.). Monte Sano, near Huntsville, 



Ala. (H. H. Smith). 

 Fig. 2. — Omphalina friabilis (W. G. B.). San Marcos, Tex. (Pilsbry and 



Ferriss, 1903). 

 Fig. 3. — Omphalina cuprea ozarkensis P. and F. Magazine Mountain, Ark. 

 Fig. 4.— Omphalina friabilis W. G. B. Mablevale, Ark. No. SI, 115 A. N. 



S. P. 

 Fig. 5. — Omphalina friabilis W. G. B. Immature. Wyandotte, Okla. 

 Fig. 6. — Omphalina pilsbryi Clapp. Near Wetumpka, Ala. No. 87,349 



A. N. S. P. 



