86 
to the bases of the tentacula, interspersed with two or three shades of 
brown in the form of stripes or spots: in some specimens a circle of 
very pale spots with darker margins surrounds the mouth. The base 
of each tentaculum is very dark and is surmounted by a broad band 
of white or buff, the upper portion shading off to a clear pale pel- 
lucid brown, on which are three narrow distinct white rings, their 
breadth and the interspaces diminishing rapidly as they approach 
the tip. These animals are capable of assuming a great variety of 
shapes, and even when fully expanded sometimes elongate themselves 
to the extent of 14 inch, or contract to little more than a 3 of an 
inch. They feed readily in confinement ; but those that had buried 
themselves in the sand appeared best able to secure their prey when 
placed within reach, the others on the surface often tumbling over in 
their endeavours to get the food into a proper position for swallow- 
ing, from not having the support of the surrounding sand or mud 
natural to them when buried. They were all 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 1} inch deep, and having that peculiar 
bead-like form which has suggested the specific name of spheroides. 
There was usually a depth of 6 or 7 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 surface, 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 considerable tract of sand 
only a few yards from the locality whence these were obtained. 
June 12, 1855. 
W. Yarrell, Esq., in the Chair. 
The following papers were read :— 
1. On two New Species or Hummine Birps. 
By Joun Gov tp, F.R.S. 
I bring before the notice of the Meeting two species of beautiful 
Humming Birds, which I believe to be new to science: they belong 
to that section of the Trochilide to which the generic appellation of 
Heliothriz has been given: of this form only three species have 
