204 CALCAEEOUS SPONGES. 



according to Dunikowski they are composed of small uniaxial spicules associated 

 with large three-rayed forms. 



Distribution. Upper Green Sand : Warminster. Cenomanian : Essen. 



Family SYCONES, Haeckel. 



Genus PROTOSYCON, Zittel 1878. 



PEOTOSycoN PUNCTATUM, Goldf. sp. (Plate XXXVIII. figs. 2, 2 a~e.) 



1826-33. Scyphia punctata, Goldf. Petref. 1 Th. p. 10, t. 3. f. 10. 



1858. Scyphia punctata, Quenst. Der Jura, p. 667, t. 81. f. 79. 



1870. Scyphia punctata, O. Schmidt, Spongien-Faima des atlaut. Gebietes, p. 20, t. 2, 



f. 21. 

 1878. Scyphia punctata, Quenst. Petref. p. 333, t. 131. t. 21-27. 



1878. Protosycon punctatum, Zitt. Studien, III Ab. p. 48, t. 12. f. 7. 



1879. Protosycon jmnctatmn, Zitt. Neues Jahrb. p. 33, t. 2. f. 7. 



1883. Protosycon punctatum, Carter, Auu. & Mag. Nat. Hist. ser. 5, vol. xi. p. 34. 



Small subcylindrical sponges with truncated summits, and occasionally slightly 

 expanded bases. The usual dimensions are from 6 to 14 mm. in length, and from 

 2"5 to 4 mm. in thickness; an unusually long form, figured by Quenstedt, measures 

 24 by .3'5 mm. A funnel-shaped cloaca extends quite to the base of the sponge. 

 The walls are from "7 to 1 mm. iu thickness. The outer surface is apparently quite 

 smooth, but under a strong lens delicate vertical furrows are visible. In each of 

 these furrows is a row of minute circular or ovate canal-apertures, and still smaller 

 circular or subangular apertures are wedged in on the intervening ridges. The 

 interior surface of the cloaca is not exposed in the specimens which I have examined ; 

 but according to Quenstedt the canal-apertures are disposed in regular vertical and 

 horizontal series. 



In a thin vertical median section the walls exhibit a series of horizontal canals, 

 about -17 mm. in width, some of which are apparently open throughout, while others 

 seem to be closed either at one or both ends. These canals are bounded by tliree- 

 and foui'-rayed spicules, and sections of the spicular rays are clearly shown, though 

 the disposition of the spicules cannot be satisfactorily ascertained from a thin section. 

 In some instances the rays are arranged singly, whilst in others the rays of two or 

 three spicules are in close juxtaposition, but they are not apparently united into 

 fibres as in the Pharetrones. The spicular x-ays are about "04 mm. in thickness; I 

 have not been able to determine their length. 



Distribution. Upper Jura: Streitberg, Franconia. 



