512 F. W. GAMBLK AND J. H. ASHWORTH. 



first quite separately from the rest of the nephridium, and 

 only subsequently fuses, as is known to be the case in other 

 Annelids. The post-larval nephridium, in fact, is only com- 

 parable to, e. g., the nephridium of the earthworm minus its 

 funnel. (For further remarks on this point see p. 519.) 



A. Claparedii. — The five pairs of nephridia present in this 

 species open on the fifth to the ninth ch£etigerous annuli. 



The nephridia are much smaller than those of A. marina, 

 seldom exceeding 4 mm. in length. The dorsal lip bears 

 ten to fifteen large ciliated, spatulate, or sometimes almost 

 reniform processes, several of which may be divided distally 

 into two or three (PI. 24, fig. 29). The first nephridium bears 

 no gonad, but in other respects resembles the succeeding 

 nephridia, and is not usually reduced in any way. In only 

 one example have we found any variation from the normal. 

 In this, a specimen about 80 mm. long, there are five 

 nephridia on the left side, but only four on the right, the first 

 one being absent. 



In all our specimens of this species the secreting part of 

 the nephridium is not brown, but light yellow, there being 

 very few excretory granules present in the cells of the ne- 

 phridia of even large (80 mm. long) specimens. The secretory 

 portion of the nephridium tapers gradually posteriorly and 

 opens into the well-marked spherical or rosette-like vesicle. 



A. cristata. — There are six pairs of nephridia in this 

 species opening on the fifth to tenth ch^tigerous annuli. 



The Jamaican specimen, 47'5 mm. long, has very elongate 

 slender nephridia about 2 mm. in length. The funnel of each 

 bears about fifteen to twenty flattened processes, some of 

 which are already divided into two or three distally. The 

 nephridia of a large Neapolitan specimen (300 mm. long) are 

 naturally much larger, being 11 mm. to 15 mm. in length. 

 The dorsal lip of the funnel bears twenty to thirty processes 

 similar in shape and arrangement to those of A. marina. 

 The secretory portion is brown and the vesicle small and 

 rosette-like (being contracted in our specimens). The ne- 

 phridia of the large American specimen, 360 mm. long, attain 



