M. K. A. Zittel on Fossil Lithistidce. 393 



Melonella, Zitt. 



Siphonia p. p., Goldf ., Quenst. 



Sponge pomiform or semiglobose, with a broad or very 

 short-stalked base. Under surface with a wrinkled, dense 

 siliceous membrane. Central cavity funnel-shaped, deep, but 

 not very broad. Wall of the stomachal cavity with numerous 

 round ostia standing in longitudinal series. The principal 

 canals are curved parallel to the outer contour line and crossed 

 by a second system of rather finer water-canals, which run 

 from the base of the stomachal cavity obliquely upwards and 

 outwards. These latter (incurrent) canals open on the surface 

 in round ostia of moderate size. In worn specimens the con- 

 centrically curved canals appear as furrows radiating from the 

 vertex. Skeleton as in Cylindrophyma, in all known speci- 

 mens converted into calcite. 



In external form resembling Aulocopium and Siphonia. 

 Found only in the Upper Jura. 



1. Melonella [Siphonia) radiata^ Quenst. Jura, p. 679, 

 Taf. Ixxxii. %. 13, and Petr. cxxvi. 60-72. 



Siphonia piriformis p. p., Goldf. xxxv. 10 (uon vi. 7). 



Lecanella, Zitt. 



From depressed funnel-shaped to basin-shaped, thin-walled, 

 both surfaces with fine pores, with no developed canal-system ; 

 wall becoming rather thinner towards the upper margin. 

 Skeleton consisting of irregularly branched corpuscles of con- 

 siderable size, having 4-6 smooth branches spreading from a 

 nodiform or discoidal centre, and dividing at the ends into two 

 or three short, rounded, conical branchlets. They bear no pro- 

 cesses. The superficial corpuscles are more regular in form^ 

 and may perhaps be regarded as greatly modified forked an- 

 chors with a short shaft. The surface is also covered with 

 large simple bacilli and innum.erable Oeodia-Yiko, spherules. 



A fragment of a very depressed funnel-shaped specimen 

 from the White Jura e of Sontheim indicates a diameter of 

 150 millims. The corpuscles are loosely united and form an 

 irregular network, reminding one of the latticed texture of the 

 Hexactinellidffi. This texture distinguishes the sponge from 

 Platychonia, which it otherwise closely resembles. This 

 species is named Lecanella paterceformis. Probably Quen- 

 stedt's Spongites jlahellum (Petr. cxxxi. 7) also belongs here. 



Mastosia, Zitt. 



Sponge nodular, with a broad hollowed base. Upper sur- 

 face with numerous large mammiform tubercles. The surface 



