MOLEUSCA 391 
The question whether these forms—when sinistral—belong to Physa or Limnaea, 
has for long proved to be a difficult one. Gould, when describing his Physa retcculata, 
remarked “its form is so much that of a reversed Lzmnaea that | am almost tempted to 
consider it one.” Pease, in his review of the Hawaiian species, stated that he was 
“confident,” having examined the animals of several hundred specimens, that there was 
no species of Physa in the Islands. He also remarked that sinistral and dextral 
specimens of the same species may be found together. Prof. E. von Martens, in 1866, 
expressed the view, here adopted, that these Hawaiian forms were really sinistral 
species of Lzmnaea. 
As shewing how little the literature has been studied, I may remark that as late 
as 1889 Mr Cooke (P. Zool. Soc. London, 1889, p. 142), when pointing out the 
affinities with Lzmnaea of the so-called Physae of Australia, notes that ‘Tryon 
mentions, but I have failed to trace on what authority, that sinistral Limnaeas occur 
in the Sandwich Islands.” 
Mighels described (P. Boston Soc. 11. p. 21) two species, producta and umbzlicata, 
as Physae: according to Pease the types were destroyed by fire and, as the species 
are unidentifiable from the diagnoses only, I have omitted them. 
(1) Limnaea aulacospira Ancey. 
Limnaea aulacospira Ancey, Naturaliste, (2) x1. (Dec. 1889), p. 290; Sykes, 
P,.Malac. Soc. London, m1. pl. xu. fig. ro. 
Has. Maui (Ancey); Haleakala at 5000 feet, and Iao Valley (Perkins). 
(2) Lemnaea binomints, nom. nov. 
Physa sandwichensis Clessin, Conchylien-Cabinet, Piysa, p. 342, pl. xivi. fig. 7 
(1886). 
nec Limnaea sandwichensts Philippi. 
Has. Hawaiian Islands (Clessin).—Oahu, Mts. near Honolulu (Perkins). 
(3) Lzmnaea compacta Pease. 
Limnaea compacta Pease, Amer. J. Conch. vr. (1870), p. 6, pl. 11. fig. 4. 
Limnaea ambigua, Pease, t. c. p. 6, pl. m1. fig. 5. 
Physa flavida Clessin, Conchylien-Cabinet, Physa, p. 364, pl. LI. fig. 9 (1886). 
Has. Oahu (Pease).—(as L. amdigua) Kauai, Kapaa (Baldwin).—(as L. compacta) 
all the Islands (Baldwin). 
185 18k, lls 51 
