!.')(» CALIKOKNIA ACADKMY OK SCIENCES. 



peculiar tis.siio wliicli Mils niucli of tlio co'lomic cavity. This tissue cons^ists of large, 

 more or less connected cells, very nuicli like tlie co'lomic ^lamUilar cells surrounding 

 so in.uiy nephridia. These cell masses are more or less difTuse, and appear not dis- 

 tinctly connected with aiiv of the interior origans of thi Imdv. A inonsr these cells 

 are found scattered aljout large masses of spermatogonia, all in about the same stage 

 of development. There are also numerous small free cadumic cells, such as found in 

 all earthworms. 



Xephridia. There is one pair of mega-iiephridia in each somite. The 

 nephridium is very large, projecting above the lateral line of the l)ody. The nephro- 

 pores — at least some of them — are seen outside of or more dorsal than sette 4. The 

 nephrostome again is as usually seen very near seta- 1. There are no glandular 

 eoeloraic mantles on any of llie mpliridia. Tlie anterior fold is much wider then the 

 posterior one.. The windings are very deep and twistiil, and the spur generally sigmoid. 

 The outlet duct, which is tapering towards the pore, is much darker than the other 

 ducts. Tts prolongation into the anterior fold forms there the central wider canal, 

 which is also darker than the other two. The canal in the bridge continues forwards 

 and upwards through the anterior fold, ami is there the posterior one of the three 

 canals. 



Vatfcular i^ystem. The ventral and dorsal longitudinal vessels are both single. 

 Tiiere are connecting vessels in somites vii to xii. In x, xi and xii, these vessels are 

 very large, and take the form of so-called hearts. Each heart consists of four or five 

 links, increasing in thickness upwards. Between each two links there is a thick 

 circular valve. Similar valves are seen also in the dorsal vessel at the junction with the 

 hearts. At the base of some of the valves are seen two row"s of very large cells, the 

 nuclei of which are about 3 to 4 times larger than the nuclei in the valve cells (fig. 

 83). All the valves in the hearts point downwards or ventrally. There are no 

 glandular cells in the vessels, such, for instance, as are found in Pontodrilus, etc. 



Posterior to the hearts we find long, tubular connecting lateral vessels, between 

 tlie dorsal and ventral trunks, in the anterior part of each somite. These vessels, one 

 pail- in each somite (fig. 8(5), are of even thickness throughout, but with two short 

 kiioli-likc diverticula, one al)ove the other, about ('(pial distances from each other and 

 from the longitudinal vessels, lioth the dorsal vessel, as well as the laterals, are 

 thickly covered with codomic chloragogen cells of a yellowish opaque color. These 

 cells do not cover the ventral longitudinal vessel. These lateral ves.sels contain no 

 valves. 



,Ea( h valve consists of several circular rings, each containing a number of 

 muscular strands enclosed within a common membrane. In longitudinal sections of 

 the vessel most of the nuclei lie parallel with each other, but llu' outsiile ones run as 

 the periphery in a circle. The smaller valves consist each of only one such lobe (tig. 

 T3a), while the large ones are composed of several (fig. Tab). 



