SKA-URcnixs. 451 



Genus 1. DiscoiDEA Agassiz. 



With the chai-acters of the subfamily. 

 Genotype. D. suhucula Leske. 

 Lower and Ujijyer Cretaceous. 



Family III. CONULID.E. 



Holectypoida with a posteriorly elongated or circular ambital 

 outline. Usually tall and coiical adapically; flat or subconvex 

 adorally. Peristome small, slightly elliptical and sometimes 

 oblique, with the perignathic ridges of equal height wath the 

 processes, the whole girdle leaning against an internally thickened 

 portion of the adoral surface. Branchial incisions very slight. 

 Penproct small, marginal. Ambulaci-a of compound plates 

 almost throughout, pore-pairs definitely triserial near the 

 peristome. Interambulacra multituberculate, with both ad- 

 median and adradial series sloping adorally, and often in linear 

 sets of thi-ee instead of two on each plate. Granulation irregular, 

 granules_ sunken on the adapical surface. Apical system with 

 four genital plates only. The two posterior oculars meet along 

 the middle line, and are larger than the other three. No 

 internal buttresses, but a marked thickening of the interradial 

 parts of the adoral surface. Kadioles similar to those of Dis- 

 coidiidae ; but in addition short ? pedicellaria-stumps arising from 

 the invaginated granules. 

 Lover to Upper CreUtceous. 



Genus 1. CoxuLus Leske. 



With the characters of the family. 

 Genotype. C. albogalerus Leske. " 

 Lower and Upper Cretaceous. 



IxCERTyE SEDIS. 



DisCHOLECTYPus Pomel. 



Holectypoida Avith the characters of Canholectyptis except in 

 the amlndacra, which are composed of compound ialates throueh- 

 out, as m the Conulid*. 



Genotype. D. meslei Gauthier, 



Lower Cretciceous. 



Discussion of the Systematic Position of Genera formerly included 

 among the Holectypoida, but now removed from the Group. 



Plesiechinus Pomel. 



This genus (or subgenus) included Pygaster semisulcatus 

 Phill. and other species related to it. As P. semisulcatus is the 



29* 



