172 RESEARCHES IN HEI.MINTHOLOGY AND PARASITOLOGY. 



slightly uneven on the outside, and sometimes feebly annulated. It 

 is attached partly along its length to fixed objects, with the greater 

 part free, directed downward and pendent. Most specimens observed 

 were single, but several were found in which two or three tubes were 

 conjoined, and in one instance five tubes, with remains of others, 

 were given off in a candelabra-like manner from a common stem, as 

 represented in Fig. 2, plate IX. From the open mouth of the tube 

 the worm protrudes its head and spreads its crown of ciliated ten- 

 tacles in the same manner as in more tubicolous annelides. The 

 simple tubes range from two to four lines in length by the one-fifth 

 to the one-fourth of a line in width. 



Manayunkia is very sensitive, and on disturbance withdraws deeply 

 into its tube, so that half the length of the latter may be removed 

 before reaching the worm. The little creature clings tightly to the 

 inside of its habitation, apparently mainly b}^ means of the minute 

 podal hooks of the posterior segments of the body. 



The mature worm (Fig. i) is from three to four millimeters in 

 length by about one-fourth of a millimeter in breadth, and is divided 

 into twelve segments, including the head. The color is translucent, 

 olive green, with the cephalic tentacles of a slightly brownish hue. 

 As the worm shortens, the segments become more bulging laterally 

 and the constrictions deeper ; in elongation the segments become 

 more cylindrical and the constrictions less marked. When the 

 worm is elongated it is of nearly uniform width for about three- 

 fourths of the length, and then slightly tapers to the end, or is a 

 little widened again in the two .segments before the last. The head 

 is about as broad as it is long, and is surmounted by a pair of lateral 

 lophophores supporting the tentacles. Its border above projects 

 dorsally into a short rounded process. The succeeding four seg- 

 ments of the body are about as broad as they are long, and nearly 

 of uniform size : the next one is somewhat longer than those in 

 advance. The seventh segment, in all the mature worms obser\^ed. 

 greatly exceeded any of the others. It was usually twice the length, 

 and differed from them in having an abrupt expansion at the fore 

 part, which suggested the production of a head prior to the division 

 of the worm ; a process, however, if it occurs in ManayiDikia, I had 

 not the opportunity of observing. The succeeding segments, smaller 

 than the anterior ones, differ little in size, except the last two. The 

 terminal segment abruptly tapers from above its middle to an ob- 

 tusely rounded extremity. When the worm protrudes from its 

 tube, the lophophores are reflected from the head, and they exhibit 

 a double row of tentacles extending forward. The number of ten- 



