164 MR. F. E. BEDDARD AND MISS FEDARB ON [JlUie 17, 



3. On a new Coelomic Organ in an Earthworm. 

 By Frank E. Beddard, M.A., F.R.S., and S. M. Fedarb. 



[Received May 13. 1902.] 



(Text-figures 36-39.) 



The following observations relate to Pheretima [Perichceta) 

 posthuma, and were made upon some well-preserved material from 

 Calcutta which we owe to the kindness of Mr. F. Finn, F.Z.S., 

 Deputy-Superintendent of the Indian Museum. In dissecting a 

 number of these worms, a series of sac-like structures were plainly 

 observable upon the floor of a cei'tain number of segments in the 

 middle of the body. The accompanying figure shows the general 

 appearance of these when magnified by a hand-lens (text-fig. 36), 

 from which it will be seen that the structures in question have 

 the form of an hourglass, or a double cone with the bases of the 

 two cones distant and their apices in contact. Ventrally, these 

 sacs come neai- to the ventral nerve-coi'd ; but doisally they do 

 not reach the opposite side of the body. They occupy in fact not 

 more than a fourth or fifth of the total circumference of the body- 

 wall. They are symmetrically disposed fi'om segment to segment ; 

 that is to say, they occupy the same position exactly in consecutive 

 segments. It is easy to see, merely with the u.se of a lens and a 

 dissecting-needle, that these structui-es ax-e cavities formed by 

 a membi'ane, which is anteiiorly and posteriorly, but not laterally, 

 attached to the parietes of the body. A needle can be readily 

 slipped under the sac at each end. They may be said, in fact, to 

 end laterally by a, wide funnel-shaped mouth, the coi-nei'S of which, 

 as is shown in the drawing already referred to, are somewhat 

 drawn out so as to offer a firmer basis of attachment, like the 

 ropes of a tent. In the middle, the surface of these chambers is 

 quite convex upwards; and at the "waist," where the two cones 

 join by their apices, there is a considerable naiTowing marked by 

 the passage of a strong blood-vessel. These cavities ai'e, however, 

 not equally marked in all the specimens of this eai'thwoim which 

 we dissected ; they are much more conspicuous in some than in 

 others. We thought it possible to detect a relation between them 

 and the glands attached to the septa just above the intestine — 

 those small and also apparently crelomic structures which one of 

 us has desci-ibed in several species of this genus of earthworms \ 

 "Where the glands lying above the intestine were well developed, 

 it appeared to us that the ventral c(elomic chambers were also 

 particularly conspicuous. 



We do not, however, venture to insist ujDon any sj^ecial relation- 

 ship between these two series of organs. These pouches do not run 

 continuously through the body of the worm. They begin behind 

 the spermiducal glands at about segment xxii., and are seen to 

 increase gradually in size up to as far back as segment xl. For 

 about twenty segments they are at their prime. After this point 

 they get smaller and often ii-regular ; but they extend right to 

 > Beddard, P. Z.S. 1890, p. 61 (" Glj'cogenic organs"). 



