.in.) 



Hall, a* figured liy \Vhittield,* but i- distinguished from that a- from other species 

 ly the rapid expansion and absence of constriction in the body-chaml>er. 



Formation and locality. In th . < at Minneapolis 



Xtuntm Rtyitttr, No. 5048. 



1 U1TOCKRA8 CtiKM.'t I.I M //(//, 1 V| 



PI. > l. 



Cfrloeenu eomiculum MALI., 1862. Bept. Ocol. Surv. Wisconsin, p. 41, fltfs. 1, 2. 



Shell -mall, sh-nder. with graceful curvature, making less than one volution. 



Surface nearly equally rounded, somewhat hroader on the doreura. Transverse 



on nearly circular. Septa very gently and regularly concave. Sipho ventral. 

 infra-marginal, minute. distant hy twice its diameter from thy margin. 



Tin-it- are two specimens of this little species, both preserved as internal ra-t- 

 in crystalline calcite. Imt one shows the character of septum ami sipho ami neither 

 indicates the distance between the air-chambers. Knough, however, is retained of 

 tln> form of the shell and its curvature to show its agreement with this species. 



The larger of the two incomplete examples measures, along the ventral 

 curve. :10 mm.; along the dorsal curve. 21 mm. At the distal extremity of the 

 specimen which is not far from the apex of the shell, the diameters are 2.5 and 

 . mm., while at the proximal extremity the dorso-ventrul diameter is 8 mm. ami 

 the lateral diameter 9 mm. 



Formation and locality. -In the Ualuna shale*. Warsaw. Minnesota. Collwiion <>f W. II - ..n.-iil. 



1 MM'iCBRAS NORWOODI, .-/'. n- 

 108. 7-. 



The sperimen upon which this species is based retain- the entire l>o<ly-cliamber 

 anl six air-chamliers. The form of the shell is suberect, gently increasing in con- 



ty from the base of the specimen to the base of the body-chamber, thence 

 gradually contracting to the aperture but forming no distinct constriction. The 

 -hell is stout, v.ith liroad dorsum. broad sides and a somewhat narrowed or laterally 

 compressed venter. The transverse section is oval, with diameters as 5 to 6. the 

 greater dimension l.eing doreo-ventrally Tin- diameter at the 7th septum 

 mm.; at the aperture 22.5 mm. The sutures are nearly transverse with very low 

 and broad lateral lobes, an indistinct dorsal saddle and more conspicuous and 

 subacute ventral saddle. Throughout their extent the sutures are minutely un- 

 dulated, these undulations being most clearly shown on the sides where the upward 

 curves of each seem to coincide with obscure longitudinal ridges on the surfa* 



Oeolocr of WtoomnU. <roL I*, pi. ra. In- '- 



