94 
SAGAETIAD^li. 
sometimes three or four inches below the surface. They 
are all equally sensitive, shrinking on the slightest alarm.” 
Mr. Hohlsworth found the species under circumstances 
which deceived him into the belief that it was a per- 
manently free form, and he accordingly named it ScoIantJius 
sphceroides.^ “ The specimens were found near low- water 
mark, imbedded in the fine chalky mud which fills the 
crevices of the rocks at Seaford, their expanded disks being 
just level with the surface, but so nearly covered that only 
a faint star-like outline was visible ; on being touched they 
instantly disappeared; and so great was their power of 
inversion and contraction, that on digging carefully, they 
were generally found about one-and-a-half inch deep, and 
having that peculiar bead-like form which has suggested 
the specific name of sijhceroides. There was usually a 
depth of six or seven inches of mud below them ; so that 
they could not have been fastened to the rock ; and since I 
have had them at home, now nearly five weeks, they have 
not shown the least inclination to attach themselves to 
the gravel, or glass sides of the tank in which they are 
living ; three of them have burrowed into some sand on 
which they were placed, but the others remain on the sur- 
face and are but rarely contracted. Soft mud is probably 
their natural habitat, being the most easily penetrated ; 
and I could find no traces of any of these animals in a con- 
siderable tract of sand only a few yards from the locality 
Vv’hencc these were obtained.” 
My friend was subsequently convinced that lie had been 
misled by the appearance of the specimens : lie examined 
them with me, and kindly gave me one of his original 
specimens, and we were both convinced that they were of 
this species. The apparent perforation at the rounded pos- 
terior extremity could have been nothing more than the 
* Proc. Zool. Soc. ; Mar, 1S55. 
