NO. 1120. FBOCEEDIXnS OF THE NATIONAL MUSEUM. 709 



ventral valves from the Paradoxides beds of Andrarum, Sweden, I am 

 led to believe that what he considered to be an apical foramen is a 

 depression in the apex of the shell in front of the incurved beak, Avhich 

 represents a foramen which was piesent in one of tlie embryonic (nepi- 

 onic) statues, and was subsequently lost. This would involve the 

 crowding- out, as it were, of the pedicle posteriorly, the only evidence 

 of its i)resence in the adult being the narrow, slightly depressed slit at 

 the apex of the valve in some specimens. The pedicle in the adult 

 shell is i)rotruded between the two valves and separated from the 

 embryonic i)edicle opening by the growth of a pseudodeltidium. 



The examination of the somewhat closely allied form, /. panmda^ 

 shows the i»resence in some specimens of the apical depression and its 

 absence in others. In an undescribed species, I. siqyerba, still more 

 closely approaching the type /. bella in external appearance, there is 

 no trace of an apical slit or foramen. lu another species associated 

 with /. superba {I. crcnistria) the apex is rounded, while in a somewhat 

 similar but distinct form [1. penki), froni the Gallatin Eiver valley of 

 Montana, the apical slit is as clearly shown as in I. ornatella, but not 

 any apical foramen. 



Messrs. Hall and Clarke illustrate a specimen of J. bella showing an 

 apical foramen, but in the description of the figure the statement is 

 made that the foramen is not altogether distinct in the specimen.' 



The systematic position of the genus Iphulea appears to be in the 

 Js^eotremata of Beecher,^ possibly with characters that nearly place 

 It in the Protremata. If the pedicle was apical in its early stages 

 and inclosed by shell growth, and subsequently was crowded back 

 of a pseudodeltidium, it passed through the Xeotrematic stage to the 

 Protrematic. The presence of an obscure listrium in front of the 

 ai)ex of /. bella, I. ornatella, and some specimens of I. pealei, tends 

 to support this view. We also have to consider the area of the dorsal 

 valve as shown in I. pannula. In this species there is a ratiier deep, 

 convex pseudodeltidium in the ventral valve, and a clearl^^ defined, 

 depressed pseudodeltidium on the dorsal valve between the narrow 

 false areas. There is also present a narrow median groove extending 

 from beneath the apex of the valve to the posterior margin of the 

 pseudodeltidium. It is similar in appearance to the pedicle groove 

 of the ventral valve of Obolns and Rhinobohis. This suggests that it 

 may be the pedicle valve; but the presence of the listrium or embryo 

 pedicle scar on the conical valve is opposed to the interpretation. 



It may be urged that Iphidea is a true Atreftiatic genus, the pedicle 

 never having been inclosed and the slit on the ventral valve being only 

 a depression without special significance. This may be so, but the 

 impression it conveys to me is that the slit indicates a pedicle open- 

 ing near the ai)ex of the ventral valve, at an early stage in its growth, 



' Pal. N. Y., VIII, Pt. 1, (lescrii)tion of pi. iv, fig. 8. 

 2 Auier. Jour. Sci., XLI, 1891, pp. 354, 355. 



