NATURAL SCIENCES OP PHILADELPHIA. 
189 
ing fresh-water streams and ponds for Polyzoa. They had the good fortune to 
find a species of Cristatella ; being the first discovery of this genus in America. 
The locality of the polyzoon is Lily Pond, near Newport, in which it is found 
very abundantly^ adhering to the under side of stones forming the shores of 
the pond. 
In the month of August, the Cristatella masses were flattened, elliptical, 
about half an inch in length and about two lines wide, and were translu- 
cent yellowish white. About three rows of polyps encircled the masses. 
Each polyp supported on its horse- shoe-like arms seventy-two tentacles, con- 
joined at base by a delicate, festooned, areolated membrane. 
Specimens of the Cristatella, placed in a dish of water, moved at the rate of 
an inch in about twenty-four hours. 
The ova, or statoblasts, were only partially developed during ray stay at New- 
port. The present month, Mr. Powel has sent to me fully developed speci- 
mens, accompanied with a note, in which he says, " I made an expedition to 
the Lil}^ Pond, and procured great numbers of Cristatella with ova. I got upon 
one stone fifty-four separate masses, some of them one inch and three-quarters 
long and one quarter wide, of a beautiful amber color, full of ova, apparently in 
various stages of development." 
These ova are the largest that I have seen in any genus of Polyzoa. They 
are double convex lenticular, and circular, with a marginal discoidal aunulus, 
a little deeper on one side than on the other. From the inner margin of the 
annulus spring forth about seventy anchor-like appendages, of which fifty 
spring from one side, and bend in a doubly geniculate manner over the outer 
margin of the annulus ; the remaining twenty are shorter, and diverge from the 
opposite side. 
Breadth of statoblast, 1.152 mm., or about half a line independent of the 
anchors. 
This American species of Cristatella is respectfully dedicated to the sister of 
Mr. Powel, with the name of Cristatella Id^. 
From the European Cristatella mucedo^ the American species differs in habit 
as well as in several points of structure. Prof. Allman, in his valuable mono- 
graph on the Polyzoa, says, that " while the greater number of the fresh-water 
Polyzoa lurk on the under surface- of stones and in dark recesses, Cristatella 
loves to expose itself to the full light and warmth of the sun." 
The polyp of C. mucedo has about eighty tentacula; and the intestine is light 
bluish green. That of C. Idee has about seventy-two tentacula, and the intestine 
is yellowish. The ova or statoblasts of C. mucedo are about one thirty-third of 
an inch broad ; those of C. Ida are about half a line. Prof. Allman's figure 
of the statoblast of the former species represents the anchors as sigmoid; those 
of the latter species have a double elbow. 
The discovery of an American Cristatella has afforded me the opportunity of 
comparing its statoblasts with those of Pectinatella. The diagnosis formerly 
given by authors to those of Cristitella^ equally well apply to those of Pectina- 
tella^ while the statoblasts of the two genera differ in a remarkable manner. 
This is sufficiently well indicated by comparing the following description with 
that above given, of the statoblasts of Cristatella Mac. The statoblast of Pecti- 
natella magnifica is doubly convex lenticular, quadrately circular, and slightly 
curved, with a marginal discoidal annulus, much deeper on one side than on 
the other. From the outer margin of the annulus spring forth about twelve to 
sixteen straightly diverging anchors. Breadth of statoblast 0.88 mm. by 0.8 mm., 
or about the third of a line. 
Recently, Dr. Wm. Spiilman, of Columbus, Mississippi, has sent to me a de- 
scription, accompanied with drawings, of certain gelatinoid masses from the 
lakes of his vicinity, on which he desired some information. The masses, which 
Dr. Spiilman observes hang from the immersed branches of plants and dead 
sticks, at the present time, (October,) " are from the size of a hen's egg to such 
as measure 15 inches long by 12 inches in diameter." The description, draw- 
1858.] 
