164 NEREIDS. 



Specimens preserved in spirits are of a uniform pearl-grey colour, 

 with pale yellowish feet. 



Heteronereis renalis is in many respects so much like the H. lohu- 

 lata of Savigny, that I have hesitated in describing them as distinct 

 species ; but the dissimilarity in the structure of the feet, though 

 apparently slight, and difficult to be expressed in a definition, seems 

 to be of a kind that nothing less than specific origin could produce. 

 In //. lobulata the leaf-like lamina of the setigerous tubercle is 

 oval, and not more than half the size it has in H. renalis ; and the 

 foliaceous appendage to the ventral cirrus in the former is also pro- 

 portionably small, and of a roundish figure, without any additional 

 lobular appendage. 



Nereis margaritacea, described in the 'Annals,' vol. iii. p. 294, 

 is also nearly allied to this species, and is, I suspect, the same as the 

 Nereis podophylla of Savigny. It requires re-examination ; and I 

 would remark, that as these species are easily injured, and their 

 appendages tear and fold up readily, several feet ought to be ex- 

 amined before fixing on their true shape and character. I had 

 made several figures of the feet of Heteronereis renalis before the 

 one now given, which, I believe, exhibits a correct outline of its 

 ordinary conformation. 



No. XXXII. — Heteronereis renalis. 



There is such a close resemblance between the shape of the feet 

 in our Heteronereis renalis and the H. fucicola of Oersted, that 

 they might be presumed to be synonymous ; but the latter differs in 

 having very long tentacular cirri. It is also a much smaller species. 



Obs. The tentacular cirri are as long as, or longer than, the 

 breadth of the post-occipital segment, which is rather longer than 

 the second. There were 110 segments in one specimen; they are 

 crowded on the posterior portion. 



3. H. longissima, jaws obsoletely serrated at the base, plain towards 

 the points; proboscis without prickles; dorsal lobe with a com- 

 pressed crest ; the setigerous branch with a large kidney-shaped 

 lamella, and a small one of the same shape is appended to the base 



