TWENTY-FOURTH ANNUAL MEETING. 



43 



Man, from carboniferous, is another form of this genus, having a very slight form 

 of involution, with a compressed whorl and subacute abdomen. The involution is 

 very slight in this species, exposing all the internal whorls, but in the transverse 

 section of the outer whorl, and in the sutures, it is unquestionably related to the 

 species described above. The living chamber is over one-half of a volution in 

 length, but it is not certain from the drawing that it is completed. 



The species differs from (Diseites) highlandense Meek and Worthen, [see Geol. 

 Illinois, VI, p. 531, pi. 33, fig. 2,] in being much larger, in having stouter whorls. 

 The sutures are, however, evidently 

 very similar. Highlandense is de- 

 scribed as having a narrow peri- 

 phery, whereas this shell, when about 

 the same size as the specimen fig- 

 ured in the Illinois survey, has an 

 abdomen almost as broad as the 

 dorsum, and very much broader 

 proportionately than in its own 

 adult whorl. It differs from (Naut.) 

 lilanovolve Shumard, [see Trans. St. 

 Louis Acad., I, p. 190,] in size, and 

 in having whorls with more rapid 

 growth, and probably a wider and 

 deeper umbilicus than in that spe- 

 cies. 



It differs from the nearest Euro- 

 pean congener Kon. infundibiihwi, 

 as figured by De Koninck, [see Calc. 

 Carb., pi. 24.] in having a narrower 

 abdomen and a more compressed 

 form of whorl in the adolescent and 

 adult stages; also in the sutures, Fiq^ 12. 



which have a more marked abdom- 

 inal lobe. It differs from Kon. {Nau-tilus) podolskensis Marie Tzwetaev, [see Ceph. 

 du Calc. Carb. de la Russie Centrale, pi. 3,] in the young. This is similar to the 

 adult in the proportions of the parts, but in K. jiodolskensis the young whorl has an 

 abdomen broader than the dorsum. The adult of this species also has a broader 

 abdomen than the adult of our shell. The species evidently stands just between the 

 genus represented by such species as Kon. ingens, implicatum, described by De 

 Koninck, and K. podolskensis, all of which have stout whorls with broad abdomens, 

 and whorls similar to those of the young of K. umhilicahim, and those species of the 

 same genus having more contracted abdomens, like mosquensis (sp. Tzwetaev), p^cro- 

 otergatuin as figured by De Koninck, and highlandense (sp. M.and W.). 



The last whorl was considerably altered by compression on one side. 



ASYMPTOCEBAS. 



The Cry])toceras Springeri White and St. John, [see Trans. Chic. Acad., I, p. 124,] 

 is the type of Meek's genus Solenocheilus, described in the "Invertebrate Paleon- 

 tology,"' [see U. S. Geol. Surv. Terr., IX, p. 491,] and we quote from this volume the 

 following: ''The group for which Professor Worthen and the writer [Meek] used 

 the name 'Solenocheilus' is almost entirely the same for which d'Orbigny proposed 



