48 



vnh'e'?, ot'Spei'ifern mid probably to other forcij^n objects. When it 

 is'attached to tlip fenestrated ex])aiisioiis of Lyropora the fenestrules 

 are indicated ill tlie dorsal vnlve. it is srrej;arioiis. 



Foiind ill the Kaskaskia ( iroiij) at ChesU'r. Illinois, and now in 

 fh^ collection of Win. F. K. (Turley. 



Fami[,v PHOL.VDOT'TD.E. 



riKII. null's ORKKNEI. 11. sp. 



I'htlr 111. Fiij. III. (Iiiisdl ririr: Fi</. 17, iiilcrior of smnc: Fitj. 18, 



jirojilc ricir : Fl<is. Jli. 'M> (did '21, flic saiiic cii- 



liirncd ficicc tKiliiral size. 



This is a small species, collected by (t. K. (Jreeiie in the washiiiLTS 

 of the debris from tlie Hamilton (iroiip. near ( 'liarleslown. hid. in 

 general form it resembles PhoJidops cinriiiudlicnsift from the Hud- 

 son Kiver tironi). but this reseml)lance is only in the dorsal valve, 

 for /'. ciiiciinKdiciisis has a tlat ventral vahc, and a foramen at the 

 beak, that are not possessed by this si)ecics. This species possesses 

 the characters of the Devonian forms described by Prof. Hall from 

 New York, but minute comparisons are unnecessary. It is sufficient 

 to say that it is a well-marked and distinct species. 



It is in the collection of S. A. .Miller. 



CLASS (i.VSTROT'ODA. 

 lv\Mii,\ C.MA'PTK.KID.K. 



IM,.\TV(KI;.\S I.M)l.\M^NSi; II. sp. 



J'lidr / I ', /•'/'/. 7. Iiilcral riciv (if flic small upcciiiK'ii : Fiij. •^. dorsiil 



ricir: Fiij. !). a i>rrliirc: Fiij. Id. side vii'ir of ii iiiahirc 



slirll irilli pari of llir side (iml slniKilcd 



riid livol;rii diroi/. 



Species rather larLCe. 'i'lie hack of the body wiiorl. from the apex 

 to the aperture, is sharjily aniriilar and stronsjly serrated. Toward 

 the apex the shell is laterally <-om|)ressed. but it expands laterally 

 toward the ajxrture. 'i'lu' apc^x is sharply pointed. The shell makes 

 about one volution, ill nearly the same jilane. when the a])ex comes 

 Mu contact with the rapidly sprcadiiiLj body whorl. 



