ORDER III SILICISPONGIAE—LITHISTIDA 51 
Hindia, Duncan (Fig. 62). Body spherical, with pertorate periphery, 
traces of attachment wanting. All canals radiate from the centre outward. 
Skeletal elements composed of three simple rays beset with prickly tubercles, 
and a reduced button-like fourth arm. All spicules regularly disposed in rows 
parallel with radial canals. Silurian ; North America. 
Sub-Order C. ANOMOCLADINA. Zittel. 
(Didymmorina, Rautt.) 
Skeletal elements Sees) of short, smooth rays with spire inflated ends 
which give off three, four, or more simple or digitate branches ; the lutter are united 
by zygosis with processes of adjacent rays; axial canals simple. Dermal spicules 
rod-shaped monaxons. Upper Jurassic and Recent. 
Cylindrophyma, Zitt. (Fig. 63). Body cylindrical, thick-walled, attached ; 
cloaca wide and tube-like, receiving numerous radial canals, and extending 

Cylindrophyma milleporata, ao oe Upper Malm; Hochstrass. A, Two individuals, 1/) natural size. 
B, Skeleton magnified 30 diameters. C, Detached skeletal element of Cylindrophyma, 60/; (after Rauff). 
down as far as the base. External surface perforated by fine ostia. Common 
in Upper Jurassic. 
Melonella, Zitt. Skeleton apple-shaped or hemispherical, with broad hase, 
r provided with very short peduncle; base covered with wrinkled silicious 
ee Cloaca deep, funnel-shaped. Coarser canals arched, parallel with peri- 
phery ; finer incurrent canals radially directed. Upper Jurassic. J/. radiata, 
Quenst. sp. 
Sub-Order D. MEGAMORINA. Zittel. 
(Rhabdomorina, Raut.) 
Usually large-sized, elongated, smooth, bent, loosely interlocking, irregularly branch- 
ig, or only ternunally forked skeletal vlemends with simple axial canals ; interspersed 
among which small, radiciform, numerously branching elements (rhizomorins) are 
occasionally present. Dermal spicules uniaaial or grapnel-shaped. Ordovician, 
Silurian, Carboniferous, Jurassic, Cretaceous, and Recent. 
