luaiu'lios. Tt sooms quite likely that the mouth of the cup was capable of more 

 complete closure, and, on the other hand, that the retracted ])olyparium was 

 capable of considerable protrusion. 



A longitudinal median section of the singles specimen shows a dome-shaped 

 fleshy centre, or thalanuis, from the margins and summit of which most of the 

 numerous lingerdike polyp-bearing lobes arise. Some of them, however, are 

 attached to the inner wall of the cup at different levels. The central dome, it 

 should be noted, rises (j[uite freely in the middle of the cup ; its diameter is 



Fig. 5. Spicules of Stnderiotos mimbilis. — A. From the stalk. B, From the internal wall of the cup. 



C. From a polyp-bearing lobe. 



greater than half the maximum diameter of the cup. The arrangement of the 

 polyp-bearing lobes may be compared to the distribution of carpels and stamens 

 in the flower of some of the Rosacete, in which the former ai'e disposed on a 

 dome-shaped centi'al thalamus, and the latter on several whorls on the inner 

 wall of the " calyx-tube ". Or, again, the central region of our specimen may be 

 compared to the disk of a Composite's capitulum and the peripheral parts to 

 the ray-florets. Fig. 3. 



There are large longitudinal canals in the central dome, separated by 

 tough hyaline mesogloea. Very strong muscle-bands pass down their walls, 

 and there are others in the wall of the cup reaching almost to the margin. 

 These longitudinal bands pas.s for a short distance into the wis[)-like stalk and 

 gradually disappear. Numerous well-defined transverse muscles extend be- 

 tween the several longitudinal bands. 



Tfie Cup.— The cortical part of the wall of the cup, which is very definite 

 and has a thickness of about 2 mm., is extremely hard, consisting mainly of long 

 2 



