1892.] SPECIES OF EARTHWORMS. 693 



funnel of the nephridia, which lies in the segment in front of that 

 which contains the rest of the nephridia. The structure of the 

 nephridia is not that of the aquatic Oligoch^eta ; they recall those of 

 the Geoscolecidje. It is of course the reproductive organs which are 

 so different from those of the higher Oligochseta. 



The testes, as in the other species of the genus, are placed within 

 the sperm-sacs attached to the front wall of segment x. ; they are 

 also in contact with the ciliated rosettes, which open likewise into 

 the interior of the sperm-sacs. In Moniligaster barwelli I figured 

 and described the ciliated rosettes as lying in the same segment as 

 that upon which the atria open on to the exterior ; this is also the 

 case with M. beddardi and with the species described in the 

 present paper ; in those two Moniligasters the sperm-duct is very 

 short and lies entirely within the xth segment. In M. bahamensis 

 the sperm-ducts are remarkably long and much convoluted, re- 

 calhng the sperm-ducts of such genera as Pachydrilus ; they do 

 not lie entirely within the xth segment but extend forwards into 

 the segment in front. It is quite possible that the difference 

 is merely one of maturity in the various individuals. The 

 arrangement of the sperm-ducts is, curiously, the reverse of the 

 arrangement characteristic of the posterior sperm-duct of the 

 Lumbriculidse ; in these worms the sperm-ducts in question traverse 

 the septum lying behind the male pore, and then bend back to 

 traverse the same septum again. This is exactly what occurs in 

 Moniligaster bahamensis, only that it is the segment in front of that 

 which bears the male pores which is twice perforated by the sperm- 

 ducts. 1 do not, of course, intend a serious comparison between the 

 two forms in this matter ; but at any rate the disposition of the 

 sperm-ducts in Moniligaster is exceedingly different from anything 

 that occurs in the remaining genera of Earthworms. 



The sperm-sacs in the present species are restricted to the xth 

 segment ; this was the case at any rate with one of the two species 

 which I studied by means of longitudinal sections ; the segment in 

 which they lie is the xth ; as in the other species of the genus, 

 their cavity is undivided by trabeculsD, but filled with developing 

 sperm. 



The orifices between segments x./xi. lead into a pair of muscular 

 sacs ; each sac has a narrow lumen bordered by a single layer of 

 low columnar cells covered with a moderately thick chitinous layer ; 

 outside the epithelium is a mass of muscles which are somewhat 

 loosely arranged, and in the interstices of which lie groups of glan- 

 dular cells. The sac is oval in form and at the distal end the lining 

 epithelium is reflected back over a conical process which contains 

 the duct of the atrium proper ; the terminal sac with this evidently 

 protrusible structure has clearly the closest possible resemblance to 

 the penis and penis-sheath of the Tubificidce. Vejdovsky has 

 figured^ a protrusible penis in the Lumbriculid Stylodrilus — a family 

 which is in some respects nearer to Moniligaster than are the 

 Tubificidse. Among Earthworms the nearest approach to the penis 

 ^ System, u. Morph. Oligochaeten, pi. xi. figs, 11-16. 



