with a revision of the Limnoddm of Authors. 3G1 



Fig. •!. — Female reproductive system, b, Genital bladder. 



a, Uterus, s, auxiliary gland, v, Oviduct, o, Ovary. 



Fig. 3. — Male generative system, a. Foramen, b. Penis 

 c, Retractor muscle, d, Vas deferens, e, Prostate, f, Epidi- 

 dymis, h, Testicle. 



Fig. 1. — Nervous system. 



Fig. 5. — Circulation, h, Heart. 



Fig.6. — a, Tup view of ova capsule of Pompholyx solida. 



b, Section of the same. 



Fig. 7. — a. Shell of Pompholyx var. solida. b, Side view of 

 the eye. 



Fig. S. — Teeth of Physa humerosa slightly separated, a. 

 Uncinal teeth, b, Pleurals. 



Fig. 9. — Teeth of Pompholyx var. solida. a, Rhachidian 

 tooth. 1). Side view. 1, First pleural, c, Side view. 5, Fifth 

 pleural. 8, Eighth pleural. 10, Tenth do. 11, Eleventh do. 

 18, Eighteenth lateral or first uncinal.* 



Fig. 10. — z, Rhachidian tooth of Zimnwa stagnalis. x, ditto 

 of Planorbis lentus. o, Rhachidian tooth of Physa humerosa. 



Fig. 11. — a, Buccal plate of Pompholyx var. solida. b, ditto 

 of Physa acuta (from Moquin Tandon.) 



Fig. 12. — Buccal plate ot'Zimnma stagnalis \ Moquin Tandon >. 

 1, 1, Accessory lateral plates. 



Fig. 13. — Rhachidian tooth of Acella g, ■>><■;/ ;.,-, .lay. 



Fig. 11. — Rhachidian tooth of Carinifex \> wbe?Tyi. 



* As comparisons may be instituted between this and other published li^ures 

 of the dentition of PompJwlyx, it may be well t" bate that some twenty-li 

 specimens of the radula have been critically examined ami compared, and 

 their agreement with the present figure is indubitable. Tin: -|» ■• inn us wore 

 examined by the writer, ami also by Prof. Theodore Gill of the Smithsonian In- 

 stitution, Mr. W. G. Binney, and Mr. Thomas Bland. 



To Mr. Binney I am under gTeat obligations for his kindness in assisting 

 me to obtain for examination his original specimens of the radula of the 

 typical Pomphetyz effusa, and f or opportunities of looking at his original pho- 

 tographs, taken from the same by Mr. Samuel I'owel. 



juxe, ib~o. 24 Ami. Lrc. Nat. Hist. Vol. IX 



