43 



The resemblance to P. ancillaria, in the younger specimens, is 

 very striking ; the older ones are more like P. tabulata, but the 

 last whorl is merely gibbous and not angular. P. Novce Hoi- 

 landice, is somewhat similar, but is much more elongated, and 

 neither angular nor gibbous. 



Physa sinuata. Testa parva, ovata, cornea, arcuatim striata: 

 spira acuta; anfr. 5 rolundatis postice sub-angulatis ; sutura 

 profunda : apertura obovata, angusta, antice sub-effusa, postice 

 emarginata ; labro antrorsum arcuato ; columella incrassata, sub- 

 perforata, reflexa. Long. £, lat. { poll. Hab. Feejee Islands. 



Remarkable for its thickened inner lip, and for the advancing 

 outer lip and consequent posterior sinus and arched striae of 

 growth, found in no other species except P. gibbosa. 



Physa reticulata. Testa tenuis, elongata, ovato-conica, fulva, 

 striis subtilissimis decussata : spira anfr. 4-5 ventricosis ; sutura 

 per-profunda : apertura obovata, dimidiam testae longitudinis vix 

 superans; columella rufa, valde plicata. Long. -J^, lat. ^ poll. ; 

 of another, long. J-, lat. £ poll. Hob. Sandwich Islands. 



Remarkable for its general color, the color of the pillar lip, its 

 decussated surface, and its very tumid whorls. Its form is so 

 much like that of a reversed Limnea, that I am strongly inclined 

 to believe it to be one. Probably the Limnea Oahuensis, Sou- 

 leyet, (Voy. de la Bonite,) is the same ; but unfortunately the 

 animal there given is so indefinitely figured as to leave it doubt- 

 ful whether it is really a Limnea or a Physa. 



Physa virginea. Testa elongato-ovata, tenuis, fragilis, lucida, 

 nitida, alba : spira acuta, anfr. 5 convexis, postice subangulatis : 

 apertura elongata, obovata, postice acuta; columella leviter pli- 

 cata. Long, f-, lat. T 5 6 - poll. Hab. Rio Sacramento, California. 



The porcelain-like structure and color of the specimens seems 

 not to be merely the effect of bleaching. It is one of the most 

 elongated species, but less slender than P. liypnorum and more 

 like P. gyrina or P. rivalis in form, but is a far more delicate 

 shell. 



Physa venustula. Testa parva, ovata, pellucida, nitida, di- 

 lute cornea: spira elevata, anfr. 5 ventricosis, postice subangu- 

 latis: apertura ovata; columella valida, albida, valde sinuata. 

 Long. •&, lat. ^ poll. Hab. Lima. 



