LIFE-HISTORY OF GORDIUS. 329 



Whilst parasitic in insects, the Gordius is bathed in a rich and highly aerated nutri- 

 tive material, and would thus not appear to require either an ai^paratus for the inges- 

 tion of food nor one for respiration. Perhaps, too, on account of the absence of a 

 digestive and respiratory apparatus, when the Gordius first escapes from its abundant 

 provision of " aerated bread," it is stimulated to incessant activity in the water to 

 fulfill at least its respiratory need. 



The generative apparatus of the female consists of a pair of ovaries, contained in 

 the interior cellular tissue of the body, extending the greater part of the length of 

 the latter on each side, and conjoining in a common receptacle below, which termi- 

 nates at the genital pore. In the male the testes hold a similar relationship, and ter- 

 minate in like manner. 



Of other interior organs, there is a tubular gland extending through the axis of the 

 body, and a cylindrical cord, apparently muscular, extending along the ventral side. 



The nervous system consists mainly of a cord, without distinct or separate ganglia, 

 extending along the ventral side, between the muscular cord just indicated and the 

 general envelope of the body. In the head the nervous cord divides on each side of 

 the muscular cord, and, according to Dr. Meissuer, becomes continuous with a ring 

 surrounding the gullet. No eyes or other organs of special sense appear to exist. 



The external integument of the body consists of a thin cuticle of pavement-like 

 cells, and a thick dermis. This is composed of layers of fibers which pursue a spiral 

 direction around the body of the worm, alternating or crossing in the successive lay- 

 ers. Within the thick skin of the worm there is a thicker muscular layer, composed 

 of longitudinal fibers. 



The Gordius is a wonderfully prolific animal. The mode of impregnation I have 

 not observed. In the European Gordius aqiiaticus, Dr. Meissner observed that the tail 

 end of the male wound spirally around that of the female, and by its forked extremity 

 grasped that of the latter, while the genital pores were closely applied together. 



The Variable Gordius and the Long-lobed Gordius extrude their eggs in a long, nar- 

 row white cord, from between the lobes of the tail, as represented in Fig. 64, h. I 

 observed a Variable Gordius, 9 inches in length by 2-5th8 of. a line in thickness, com- 

 mence laying eggs, and continue the process very slowly and gradually during two 

 weeks. They were extruded in a delicate cylindrical cord, resembling a thread of 

 sewing-cotton. At first it broke ofi", as extruded, in pieces about a foot in length, but, 

 towards the end of the process, the cord appeared to be less tenacious, and broke off in 

 j)ieces a few inches, and even a few lines, in length. The pieces in the aggregate meas- 

 ured 91 inches; the thickness of the cord was about the 1-lOth of a line. The eggs 

 are very minute, and in the cord were compressed together so as to be polyhedral. In 

 a transverse section of the cord I counted about 70 eggs, and in the length of l-40th 

 of an inch 26 eggs, which, by calculation, gives 6,624,800 as the whole number of eggs 

 in the cord. The eggs when isolated assume an oval shape, and measure about the 

 l-750th of an inch long by the 1-lOOOth of an inch broad. 



The development of the young from the egg is readily observed from day to day; 

 and it takes about a month before the process is completed. The globular mass of 

 yolk in the center of the egg undergoes segmentation, and increases in bulk until it is 

 finally resolved into an oval mass of granules, occupying the greater part of the inte- 

 rior of the egg. Gradually the mass assumes the appearance of a worm doubled upon 

 itself, as seen in the magnified view (Fig. 64, o). In about four weeks the Gordius 

 reaches maturity, and escapes from the egg totally different in appearance from the 

 parent (Fig. 65, p, q, r). 



The newly-developed Gordius is about the l-450th of an inch long. The body is con- 

 stricted just posterior to the middle, so as to appear divided into two portions, remind- 

 ing one of the two divisions of the body in spiders. The anterior thicker portion of the 

 body is cylindrical, distinctly annulated, and contains a complex apparatus which the 

 animal is capable of protruding and withdrawing. The posterior part of the body is 

 cylindrical, annulated, and rounded at the extremity, which is furnished with a pair 



