106 SILICEOUS SPONGES. 



specimens from Germany ; but as their spicular structure has been obliterated, a 

 satisfactory identification is impracticable. 



Distribution. Upper Chalk : Croydon, Surrey ; South of England ; Coesfeld, Dahl- 

 feld, AVestphalia. 



CosciNOPORA QumcuNciALis, Toulmin Smith, sp. 



1847-48. Ventriculites quincuncialis, T. Smithy Ann. & Mag. Nat. Hist. 1 ser. vol. sx. t. 7. 

 f. 7, and 2 ser. vol. i. p. 207. 



Sponges narrow funnel-shaped, gradually tapering to a cylindrical stem, which 

 gives off horizontal root-like processes at its termination. An average specimen is 

 70 mm. in height, and 25 mm. in width at the summit. 



The walls are from 2 to 2"5 mm. in thickness; the canal-apertures on the outer 

 surface are about '5 mm. in diameter, and disposed in very regular quincunx. Here 

 and there, in some specimens, traces of spicules can be detected ; they appear to have 

 had compact nodes. The spicular structure of the stem is formed of elongated 

 irregular spicules ; this structure overlaps the regular mesh-work of the wall in the 

 lower part of the body of the sponge. 



This species is readily distinguished from C. infundibiiliformis by its narrow 

 elongated form and the smaller size of the canals. Toulmin Smith states that the 

 walls of this species are folded the same as iu Ventriculites, but I am unable to 

 recognize this character in his typical figured specimen. The specimens are preserved 

 in flint, and all appear to be incomplete at the summit. 



Distribution. Upper Chalk: Croydon, Surrey; Arundel, Sussex; Beckhampton, 

 Wiltshire. 



Family MELLITIOKID^E, Zittel. 



Genus APHROCALLISTES, Gray, 1858. 



Aphroc.\llistes alveolites, Roemer, sp. 



1840. Scyphia alveolites, Roemer, sp., Nordd. Kreide, p. 8, t. 3. f. 6. 



1877. Aphrocallistes alveolites, Zittel, Studien, I Ab. p. 49; Neues Jahrbucb, p. 359. 



The specimens which I refer to this species consist of two small fragments of the 

 sponge-wall, whicli is composed of prismatic canals 1'75 mm. in diameter, with very 

 delicate partitions. The spicular structure is now in the condition of iron peroxide ; 

 aiid as the character of the mesh cannot be distinguished, there is some doubt as to 

 the correct identification of the specimens. 



Distribution, Upper Chalk : South of England ? 



