338 M. K. A. Zittel on Fossil LitMsiidcp . 



solid covering-layer ; but this also consists of a close tissue of 

 filigreed siliceous corpuscles, smaller than those of the wall, 

 and with the processes sometimes more strongly developed. 

 These are probably young skeletal corpuscles. This surface- 

 layer, which also forms the tubularly elongated walls of the 

 oscula, is separated by treatment with acid ; and then there 

 are usually seen on the surface simple or forked horizontal 

 canals Avhich open into the vertical tubes of the oscula. Of 

 free siliceous structures there are straight or bent, pointed or 

 blunt, bacillar spicules of different sizes. 



This genus very closely approaches the existing genera 

 Azorica and Leiodermatium^ both in external form and in the 

 microscopic structure of the skeleton. All three are charac- 

 terized by the absence of a special surface-layer composed of 

 anchor-shaped or disciform spicules, this being replaced by a 

 dense layer of young corpuscles. Verruculina differs from 

 these two genera in the larger size and gnarled condition of 

 its skeletal corpuscles. From Chenendopora^ Lamx., this 

 genus differs in its wart-like oscula and short curved stomachal 

 cavities, which reach only to the middle of the wall. Chenen- 

 dopora also is always funnel- or cup-shaped, and has usually a 

 long root traversed by vertical tubes. 



All the known species of Verruculina are from the Middle 

 and Upper Cretaceous. 



1. Manon micrommata^ F. A. Rom. Kr. i. 4 ; Quenst. Petr. 

 cxxxii. 52. Quadratus-chalk, Sutmerbeg. 



*2. Manon seriatopora^ F. A. Rom. Kr. i. 6. Quadratus- 

 chalk, Sutmerberg. 



*3. Manon Phillipsii^ Reuss, Bohm. Kr. xix. 7—9. 



Clienendopora undulata, Gein. Elbth. vii. 5, 6 (non C. undulata, Mich. 

 xxxiv. 3, necnon C. fungifm-mis, Lamx., Mich, xxxiv. 2) , Ceno- 

 manian ; Bohemia, Saxony. 



4. Manon distans, F. A. Rom. Kr. p. 3. Quadratus-chalk, 

 Goslar. 



*5. Chenendopora aurita^ F. A. Rom. Spong. p. 43. Qua- 

 dratus-chalk, Hanover. 



6. Spongia marginata^ Phill. Yorkshire, i. 5 ; Quenst. Petr. 

 cxxxii. 54. Upper Chalk. 



Amphithelion, Zitt. 



Manon p. p., Rom., Reuss. 



Verrucoccdia and Chetiendopwa p. p., F. A. Rom. 

 Diplostoma p. p., and Chenendroscyphia p. p.. From. 

 Stelgis p. p., Cladostelgis p.p., and Pleurostelgis, Pomel. 



Sponge funnel-, basin-, ear-, or leaf-shaped, rarely branched, 

 stalked, on both sides with wart-like oscula, those of the 



