THE PHYLACTOLZAMATA. 369 
Fig. D represents a sprig of the Bowerbankia imbricata of the natural size, and the 
same species is shown much magnified at E. In this species the cells are aiso placed 
upon the footstalk formed by the polyzoary, but they are not grouped together as in the 
last-mentioned species. The polypes are long and slender, and the walls of the cells are 
delicately transparent, thus allowing the observer to examine the structure of the polype 
through the walls. 
A part of the digestive organs of the Bowerbankia is deserving of a passing notice. Like 
all the other species, it possesses a feathery crown of tentacles sprouting around the mouth, 
and directing the minute objects which serve it for food, from the mouth into the cesophagus, 
popularly called the gullet. In this genus, however, a further provision is made, for immedi- 
ately below the cesophagus comes a kind of contractile gizzard, lined with a marvellous pave- 
ment of teeth arranged in a tesselated formation, and capable of bruising and crushing the 
food before it is passed into the stomach and thence to the intestine. One species of this 
genus, Bowerbankia densa, is common on the English coasts, being found parasitic on /Vustra 
foliacea in patches of about an inch or so in diameter, and may be readily obtained by those 
who are desirous of studying its habits and structure. 
At Fig. F is given a small portion of a polyzoon named Buskia nitens, the former title 
being in honor of the eminent naturalist, and the latter alluding to the shinmg appearance of 
the species. 
Wurti the next descriptions our examples of the Marine Polyzoa are terminated. 
Of the Aleyonidium gelatinosum, popularly called the Sea Ragged Staff, Mermaid’s 
Glove, or more commonly, Dead Man’s Fingers, in allusion to the cold dampness of its 
surface, great numbers can be found on the sea-shore, especially after a storm, when it may be 
seen lying among the masses of sea-weed and other débris that are flung on the beach by the 
angry waves. In its natural state it is affixed by its base to stones, shells, and other supports, 
and is always extremely irregular and variable in its form, no two specimens being alike. 
When picked up, its aspect is anything but attractive, but when placed in sea-water and 
suffered to remain at rest for a while, it becomes a most beautiful object. From each of the 
tiny pits with which its surface is thickly studded, projects a polype, with a beautiful crown 
of waving tentacles, and so numerous are these polypes, that they densely cover the surface 
and render microscopic observation rather difficult. 
As in other species, fresh colonies of the Aleyonidium are formed by gemmules, which are 
given forth from the general mass, swim about freely for a time, by means of the cilia with 
which their surface is thickly studded, and when they have attained a proper age, settle down 
and at once begin to develop fresh cells on all sides. The little vesicles wherein the gemmules 
are originally formed, may be seen in the spring scattered through the transparent substance 
of the polyzoary, and looking like little white points. Each vesicle contains about five or six 
gemmules, and as it can be easily isolated, its rupture and the consequent escape of the 
gemmules can be easily seen in a moderately powerful microscope. 
Our next ample is the Pedicellina echinata. These little creatures look wonderfully like 
the common moss that grows so plentifully on walls. The cilia by which the necessary 
currents are formed in the water for the purpose of obtaining food, is similar to a tulip in its 
form. 
PAYEE AIG LO; 72M Ad, A 
Onz of the most remarkable polyzoa that at present are known to exist, is the Cristatella 
mucedo. The entire polyzoary is not only free and unattached to any object, but even 
possesses the power of locomotion. It is frequently seen’ to crawl over the stem of some 
aquatic plant. In order to qualify it for this process, the lower surface of the polyzoary is 
modified into a flattened disc, which thus becomes analogous to the foot of the gasteropodous 
mollusks already described. The substance of the disc is contractile. 
Vou. 1L—47, 
