s 



162 CAMFOKNIA ACADEMY OF SCIKNCES. 



Ovipores are separate between somites xiii/xiv, or sliorlitly on the anterior part 

 of xiv. 



Acjihrojjorc!< prominent in front of 8et;e 1 and 2 in all somites posterior to xii. 



INTKItlOI! C'HAUACTKHS. 



Bodij-irali. In .somites x to xiv the body-wall is nincli thinner on the dorsal 

 ide of the body than on the ventral side. As lienham does not mention this peculi- 

 arity in Sji. /(iiiK'^i^, and as I have not observeil it in Sp. Smithi, I take it for granted 

 that this character is peculiai' to this species. The clitellum is complete, but much 

 thinner on the ventral side between the seta-, as shown by figure 111', which repre- 

 sents the ventral body-wall in somite xix. It will be seen that the longitudinal muscular 

 layer is several times thicker lh:in tlu; transverse layer. The strands are separated 

 by irregular layers of granulated tissue of various thicknesses. The circular layer 

 again consists of oidy one row of fascicles, each fascicle being tubular, and inclosing 

 numerous irregularly distributed nuiscnlar fibers, strongly striate. When viewed in 

 cro.s.s-.section it becomes apparent that the strands of the longitudinal muscles are of 

 varying thicknes.s, the thiekcr- ones being situated nearest the coelomic cavity, from 

 there gradually decrease in size towards the circular muscles. 



('/ife/litf cellx. The clitellar cells are especially interesting on account of their 

 relationship to the cells of the tubercula pubertatis, which will be described later on. 

 Figs. 107, 108 represent a longitudinal section of the body-wall in somites xxiii and xxiv. 

 The muscular layers are much thinner, the clitellar cells are only developed in the 

 vicinity of the prostates. P>elow the clitellar cells are seen long tubular cells, some- 

 wiiat like those of the tubercula ])ubertatis, and between them are seen, now and then 

 (fig. Wi d.ch.), the deeply staining discharge chambers of the clitellar cells. The uni- 

 cellular glands, which are here very irregular, are entirely confined to the zone 

 surrounding the intersegmental grooves. In fig. 108 is seen a more magnified part 

 of the region close to the prostate. Only one unicellular gland, though of unusual 

 size, is seen. It is a stray one, as they are rare in this particular zone. The structure 

 of the clitelhnn of 8])arganophilus has been well described by Benham in his paper 

 on Spanj(iii(iiihilii>^ tame.Hix, and 1 can only add a few points ot interest. For studying 

 the clitellar and tubercula pul)ertatis cells I have used principally the iron-lack 

 Heidenhain process, but by atlding a light tint of Ehrlich-Biondi to the ammonio- 

 ferric-alum solution the most perfect dinerciitiation may be had of the various clitellar 

 elements. The clitellum in Sparganophihis contains the following various varieties 

 of cells: 



1. Kegular epidermal cells, secreting the cuticle, furnished with oval nuclei. 

 Even on the fully developed clitellum of Sji(U(janoji]n/it!< Btitliaini they occur all 

 around, both on dorsal and ventral sides. Their inner ends are drawn out into one or 

 more threads, some of which extend to the innermost margin of the epidermis 

 (fig. 103, 1). 



2. Unirclliiliir ijiihlit glands, entirely confined within the outer layer of the 

 foregoing cells. They are very irregular as to size. These cells are the only ele- 



