1856.] 57 



cream color, to a dusky ochreous yellow, yellowish brown, reddish brown, 

 light chocolate to dark chocolate brown, or to ebony black ; lustrous, often 

 iridescent in sunlight. Head surrounded by a dark brown or black ring, ob- 

 liquely truncated and terminated by a convex, translucent, whitish vesicular mem- 

 brane, at the lower part of which is a minute round mouth. Integument areo- 

 lated ; areolas irregularly pentahedral. 



Female. Lighter in color than the male, and usually much longer and thicker. 

 Caudal extremity trifurcate ; caudal lobes elongated, elliptical ; one narrower 

 than the other two. Generative aperture round, enclosed by the caudal lobes. 



Male. Usually dark-brown, often inclining to black. Caudal extremity curved. 

 Tail bifurcate ; caudal lobes curved conoidal, obtuse, divergent. Generative 

 aperture ventral, just above the caudal lobes. 



Twenty females and twelve males were found in Rancocas creek, a branch of 

 the Delaware, New Jersey, in the month of August. Length of the former 5 to 

 12 inches; breadth -^ to 2-5ths of aline. Length of the latter from 4 to 6J 

 inches; breadth l-5th to J of a line. Three females from 7 to 12 inches in 

 length, and from \ to 2-5ths of a line in breadth ; and one male 6i inches in 

 length and } of a line in breadth, Avere obtained from the Delaware river. Six 

 females and two males were obtained from the Schuylkill river. Mr. Pearsall 

 has given me eight specimens from Philadelphia Co. Prof. Agassiz has given 

 me a female 12 inches in length, from Niagara ; a male 6 inches in length and a 

 female 8 inches in length from the vicinity of Cambridge ; two females 6 inches 

 in length from Edgartown ; aud a male 3 inches in length, and 2 females 4 inches 

 and 9 inches in length from Trenton. Dr. King, of Greensburg, Penn., has 

 given me a male 5 inches in length, from his vicinity. Mr. Hazzard, of Point 

 Judith, R. I., has given me a female 10 inches in length by 2-5ths of a line in 

 breadth, from his vicinity. Prof. Kirtland has given me a male 5 inches in length, 

 said to have been passed per annum by a girl, near Cleveland, Ohio. Prof. 

 Baird has given me three males from the Susquehanna river, near Carlisle, Pa., 

 and a male and female from Lake Champlain, N. Y. 



The Gordius varius is the most common species of the genus in the United 

 States ; and it is familiar to most persons under the name of hair-worm, and is 

 erroneously supposed to originate from the maceration of horse hairs in water. 

 The species is remarkably prolific. A single female, 9 inches in length, by 

 2-5ths of a line in breadth, which I had preserved in a large vessel of water, 

 extruded from between its caudal lobes, a cord of ova, broken into segments, 

 the aggregate length of which was 91 inches, and breadth l-20th of a line. I 

 counted in each transverse disk of the cord, about 70 eggs, and in the length of 

 l-40th of an inch, 26 eggs, so that by simple calculation: 70X26X40X91= 

 the whole number of eggs deposited is 6,624,800. 



170. Gordius aquaticus ? Gmelin. 



Gordius seta Miiller, Diesing, Syst. Helm, ii, 83. 



Gordius lineatus Leidy, Pr. A. N. S., v, 263, (1851). 



Gordius rohustus? Leidy, Ibidem, 275. Body long, filiform, not narrowed an- 

 teriorly, dusky yellowish white, cream colored, white, light brown, or dark 

 brown in color, sometimes darker at the extremities, lustrous. Areolae of the 

 integument hexagonal. 



Female. More robust than the male, opaque, and lighter colored. Head ob- 

 tusely rounded. Caudal extremity truncated, rounded. 



Male. Narrower than the female. Head obtusely rounded. Caudal extremi- 

 ty incurved, bifurcated ; caudal lobes curved conoidal, obtuse, fimbriated upon 

 the ventral border with simple branching dermal appendages. 



Six males from 5 to 7J inches in length, and ^ of a line in breadth ; and one 

 female 5 inches in length, by ^ of a line in breadth ; of a dusky yellowish white 

 color, were obtained by Prof. Baird from a spring in Essex Co., New York, 

 {Gordius lineatus., Pr. A. N. S., v, 263). One female, of a light brown color, with 

 the head ringed with black, 3i inches long by l-5th of a line broad, procured 

 by Dr. W. S. Gibson, from a spring in Philadelphia county. A female of a 

 cream-color, with the head ringed with dark brown, 4i inches long by l-5th of 



