On Prophysaon, etc. 303 



low, wide, the upper margin reflected along its wfiole length and produced 

 into two oblique, broad, bluntly rounded cusps, the inner one bluntly- 

 bifid. 



Jaw (see pi. xiv, fig. 5) arched, high, ends blunt, scarcely attenuated; 

 concave margin with a broad, blunt, median projection. Upper margin 

 showing slightly the ends of subobsolete ribs, whose presence is scarcely 

 discernible on the anterior surface. Strong perpendicular striae, and 

 stout transverse lines of reinforcement. 



We have also examined the genital system and find it 

 apparently as described by M. St. Simon {I.e.). Its char- 

 acteristic is the long, flagellate penis, and long, large duct to 

 the genital bladder. (See pi. xiv, fig. 6.) The external 

 orifice of the generative organs seems, as stated by M. St. 

 Simon, to be under the mantle, not far in advance, on the 

 side of the neck, behind the right tentacle. See our re- 

 marks on the value of this character in Ann. N. Y. Lye. 

 Nat. Hist., X, p. 165. 



It is interesting to state in this connection, that we have 

 already rescued from a similar misapprehension^ one species 

 of the genus Leucochroa (L. Boissieri, see Ann. of N. Y. 

 Lye. Nat. Hist., X, p. 220), a genus separated from JleUx 

 on the same grounds as Helix lychniichus was referred to Zo- 

 nites. We cannot refrain from believing that all the species 

 referred to Leucochroa, including L. candidissima, will be 

 proved to have quadrate marginal teeth. 



The species allied to Helix lycJmuchus, also referred to 

 Dentellaria, H Isabella and H dentiens, have decidedly 

 costate jaws ; H. orbiculata and perplexa have only some 

 approach to ribs on their jaws ; the last mentioned has a 

 broad median projection. All of them have on their lingual 

 membranes marginal teeth of the type described above in 

 Helix lychnuchus.* 



*The habitat given of this species, in Albers, 2d ed. (Porto Rico), is unquestionably- 

 erroneous. It is by no means uncommon in Guadeloupe, and Pfeiffer refers it also to 

 Martinique, but we have not seen any authentic specimen from that island. 

 June, 1873. 21 Astn. Ltc. Nat. Hist., Vol. x . 



