stanton] APORRHAIDiE. 145 



Some of the shells described by Dr. C. A. White as Anchuraf fusi- 

 formis Meek, are certainly young individuals of Anchura prolabiata, 

 but the figured specimen may represent a distinct species. The form 

 of the wing seems to be different from that of A. prolabiata at any stage 

 of its growth, but as none of the surface features are preserved it is 

 impossible to determine its true relations. Prof. Meek stated that it 

 does not belong to his species. 1 These specimens came from several 

 localities in New Mexico and their associates at some of them at least 

 belong to the Colorado formation. This species, together with the 

 European species above mentioned, forms a natural group that differs 

 considerably from typical species of Anchura in general aspect, and 

 especially in the form of the wing. The subgenus (of Aporrhais) Per- 

 issoptera proposed by Mr. Tate 2 in 18G5 was evidently intended to 

 include this group. Unfortunately I have been unable to obtain the 

 original paper, in which the subgenus was described, and consequently 

 I do not know what species was taken as the type. According to Mr. 

 Gardner 3 it is equivalent to his section I of Aporrhais, and includes A. 

 parkinsoni and related forms, and also the recent A. occidentalis. The 

 latter species, which was the type of Gabb's subgenus Arrhoges, has 

 mauy features in common with the Cretaceous forms, the principal 

 difference being that it has a distinct thickened inner lip, but whether 

 it is placed in the same section with the fossil forms or not I think that 

 Tate's name should probably be applied to the latter, as he was writing 

 on " the so-called Bostellarise of the Cretaceous." More recently these 

 forms have been referred to Lispodesthes, which I regard as an entirely 

 distinct genus. 4 



Locality and position. — Sink spring and Upper Kanab valley, Utah, 

 occurring about 350 feet above the base of the Cretaceous section at 

 the latter locality. 



Genus ANCHURA Conrad. 



Anchura (Drepanocheilus) ruida White. 



PI. xxxi, Figs. 3 and 4. 



Anchura ruida White, 1876, Geol. Uinta Mts., p. 120. 



Anchura {Drepanocheilus) ruida White, 1879, Ann. Rept. U. S. Geol. Sur. Terr, for 

 1877, p. 312, PI. 7, Figs. 4a and b. 



Revised description : 



"Shell rather small; spire moderatelv elongate; volutions about 

 seven, convex; suture impressed; wing moderately large, contorted, 

 bearing at its extero-posterior corner a strong falciform process, the di- 

 rection of which is nearly parallel with the axis of the shell; the outer 



1 U. S. Geol. Expl. 40th Parallel, vol. IV, p. 161. 



'Quoted by Gabb : Am. Jour. Conch., vol. iv, 1868, p. 148. 



3 Gardner, J. Starkie, on Cretaceous Aporrhaidae : Geological Magazine, Dec. II, vol. II, 1875, p. 394. 



* See p. 146. 



Bull. 106 10 



