DALL] NOTES ON SOME UPPER CRETACEOUS VOLUTID-E . 7 



indiscriminate "lumping" of species. The fauna comprises, as well 

 as can be determined from the fine illustrations given by Zekeli, 

 without an opportunity of also consulting the fossils, two species of 

 Gosavia, G. gradata Zekeli, and G. squamosa Zekeli, the latter a very 

 coniform species and the type of the genus. There are typical 

 species of Volutodcrma; V. perlonga Zekeli (prcclonga in the legend 

 to the plate) ; V. fenestrata Miiller (non Zekeli), and the less char- 

 acteristic species V. Miilleri Dall 1 (= fenestrata Zekeli non Miiller) 

 and V . (Rostellaca) subsemiplicata Orbigny. The group of short 

 species having a somewhat nassoid aspect, usually with rather 

 numerous axial ribs and feeble spiral sculpture, which I propose to 

 separate sectionally under the name of Rostellana with V. Bronni 

 Zekeli 2 as type, comprises also V. gasparini Orbigny (acuta Zekeli 

 non Sowerby), V. acuta Sowerby (non Zekeli), V. coxifcra and V. 

 cristata Zekeli. This group is also represented in the Pugnellus 

 sandstone of Huerfano Park, Colorado, by allied species. 



In the analogous group of forms from Aachen admirably illus- 

 trated by Holzapfel in the Paleontographica, we find a different and 

 much rougher type of sculpture, with nodulation of the intersections, 

 the axial and spiral ridges more nearly equal in strength, the shells 

 smaller, the shoulder less emphasized and the posterior sinus less 

 conspicuous. In the coexisting genus Ficulouiarpha we find an ab- 

 sence of axial sculpture, the nucleus is subglobular, the shoulder 

 evanescent, the spire largely involute, giving a pyriform aspect to 

 the shell, which has a wide recurved canal in the adult. The aspect 

 strongly suggests Ficula if it were not for the heavy shell and 

 plaited pillar. This external resemblance has led several authors to 

 regard the species as a plaited precursor of Ficula. But the young 

 shell has a relatively higher spire and straighter canal with the 

 oblique plaits and globular nucleus of the Volutidce, and is not more 

 pyriform than Callipara, which no one doubts belongs to the Volu- 

 tidae. In fact, the difference in form is almost entirely, in this case, 

 due to the gradual involution of the spire with age, and the resem- 

 blance to Ficula is purely superficial. This genus retains the pos- 

 terior sinus characteristic of nearly all Mesozoic and many subse- 

 quent A'olutidae. 



A very close ally, probably only sectionally distinct from Ficulo- 

 morpha, is Glyptostyla Dall, described from the Gatun Eocene on 

 the line of the Panama canal. It differs from the Aachen fossil bv 



1 Zekeli, Gosaugebilde, taf. xn, fig. 6. New name. 

 "Zekeli, Op. cit., taf. xn, fig. g. 



