1890.] WORMS OF THE GENUS PERICH.«TA. 61 



Nephridia. 

 In describino; the remarkable nephridia of a New-World PerichcBta, 

 P. asperr/iUum (10), I pointed out that probably all Perichcetce with 

 irregular diffuse nephridial tufts — that is to say, all the species belong- 

 ing to PerichcEta, AnisochcEla, and Megascolex. as these genera are 

 defined in the present paper, — would prove to possess a nephridial 

 system of the same kind as that which characterizes P. aspergillum. 

 The pores upon the cuticle often render it possible to predict of a 

 given Earthworm that the nephridia will be found to be dysmetamerie ; 

 after finding upon the cuticle of P. houlleti numerous pores which 

 could be referred to no other known structure than totbeaperturesof 

 nephridia, I ventured to predict that this species would be found to 

 agree in all essentials of its excretory system wiih P. aspergillum. 

 Unfortunately I have not been able to" put this prediction to the 

 proof, as the specimens of P. houlleti which I have are not in a 

 sufficiently good state of preservation for sectionizing. The specimen 

 of P. indica, however, I carefully preserved, and the examination of 

 transverse, and particularly of longitudinal, sections shows that it 

 agrees with P. aspergillum in the minute structure and in the 

 relations of the nephridia. A dissection of the worm shows that the 

 nephridia do not present the regular paired condition of such forms 

 as Lumbricus ; they are represented only by minute tufts attached to 

 the ventral body-wall, especially to both sides of the intersegmental 

 septa. This condition of the nephridia would lead to the assumption 

 that a microscopic investigation of the nephridia would prove the 

 presence of numerous irregularly-disposed external pores and ccelomic 

 funnels. I made a number of longitudinal sections in the hinder region 

 of the body, and found that the nephridial tubes were in places per- 

 fectly continuous from segment to segment through the septa ; the 

 external pores also had that irregular arrangement of a large number 

 of pores per segment which is apparently to be now regarded as a 

 very prevalent condition among Earthworms. 



Spermathecce. 

 The structure of the spermathecse is illustrated in the accompany- 

 ing figures (Plate V. figs. 4, 5, 6, 8). As app-^ars to be always the 

 case in Earthworms, the diverticula have a different histological 

 structure from the pouch. The epithelium lining the pouch (see 

 fig. 6) is tall and columnar. In the diverticulum, on the other hand, 

 the structure not only differs from that of the pouch itself, but also 

 from that of the diverticula of other species of Perickeeta ; but 

 these differences are very possibly due to immaturity in the present 

 specimen. The diverticulum was filled (see fig. .5) with a perfectly 

 homogeneous fluid, slightly stained by the colouring reagent used ; 

 the epithelium lining the pouch was formed of very low cells, not 

 in the least columnar, and hardly to be distinguished from the mus- 

 cular fibres which make up the very thin walls. 



Glycogenic Organs. 

 Perichceta indica is furnished with a series of curious glandular- 



