'M>. OB SCHLOTHEIM1 \\ BB INCH. 133 



flattened tone. The reduction of the abdomen of course occurs in all species of 



. but in oth b, except B .<. it i> found only during th<- 



Quenstedl may also in part belong t.> ( 

 since two specimens from the Stuttgardl Museum of this nam.- apparent!) belong 



to tlr- iily. Tl nvelopment in one of these specimens covers about 



two thirds of the sides of the eighth whorl, and about the same age the pilae 



- the narrow abdomen, obliterating the median depression or smooth 



■one, and introducing s Beries of crenulations instead. Ilu- is s return to the 



young condition, and indicates the first degradations! or clinologic Btage. It is 



not intended by thi* to deny thai there are no young which closely approximate 



to the young ol I On the contrary, some specimens are apparently 



identical in all n xcepl the greater flatness of the whorls and the i arlier 



I at which involution appears, and the two species are connected b) numer- 



tional tonus. 



Sehlotheiniia Boucaultiana, Winn*. 



-urn in PL M. I l e . O. 



Amm I •'' '::i ■ . I pi \.-_ 



Win i (team., Beitr., IV p KM 



pi wiii. fig. 1 I 



Semar. 



This remarkable species differs from hagneUHa in about the same manner thai 



tli<> latter differs from I i. in other words, it is more involute than Lcigne- 



i. e. on about the seventh or eighth whorl at least three 



fourth* ire hidden. The pilsa are xioi so coarse as in thai -\ 



and the abdominal channel is obliterated at an earlier age and is succeeded by 



crenul ted by the pike. The sutures differ considerably. The specimen 



ned was one of D'Orbign; The same transitional forma which lead 



into other more compressed and more involute forms 



which tional to the ti /■' i They differ I I only 



in the suppression of the tuberculated pilsa, and a general tendency toward 



Sehlotheiniia D'Orbignyana, Btati 



Amm ' ' ici ) 



■ 



Tli ■ / but is not 



s<> involute. 1' iy, an extreme modification of 



' • lv compressed whorls, and acquiring in the dim 



abdomen ll more do • § ••! Walincr 



than . hut it i» even more compressed nnel more like 



( ■■■•,■ _-•• than tl I ' ' ' that of an 



and more 1 1 K « - ( 



