HETERONEREIS. 161 



proboscis ; another on an infra-labial swelling : on the inferior ring 

 there were two clusters of these prickles on the dorsal side, and a 

 series encircling the inferior half. The jaws had ten obtuse denticu- 

 lations about the middle, but both the base and apices were without 

 any. The rings were fully 100 ; the feet nearly alike. 



Taking the form of the foot to be specifical, I refer this to N. 

 fiicata. I think it remains to be proved that the serratures in the 

 jaws are specific. The superior cirrus was longer than the lobe. 



The specimen was found in the shell of Buccinum undatum, along 

 with the Hermit-lobster. 



13. HETERONEREIS. 



Nereilepa ( — ), Blainville in Diet. Ivii. 469. 



Heteronereis, Oersted, Annul. Dan. Consj). 19 ; Granl. Annul. Dorsibr. 



22, and in Kroyer's Naturh. Tids. 1842, 115; Ray Soc. Rep. Zool. 



1847, 505. 

 Nereis C, Grube, Fam. Annel. 50. 



Char. Anterior portion of the body subcylindrical, with simply 

 lobulated feet ; the posterior portion flattened, with narrower seg- 

 ments and compound feet, there being attached a foliaceous bran- 

 chial lamina to the superior setigerous branch, and another beneath 

 the inferior cirrus : dorsal lobe with a hump or crest, the cirrus 

 originating at its base : bristles compound, some with falcate and 

 some with acicular points. 



1 . H. lobulata, lobes of the feet conoid, subequal ; the dorsal with 

 its crest rather small and globular ; the cirrus smooth, scarcely 

 reaching beyond the apex ; lamellae somewhat reniform, rather 

 small, entire ; inferior cirrus with two papillae at its base. Length 

 7" ; breadth 4'". 



Lycoris lobulata, Savign. Syst. Annel. 30. Lam. Anim. s. Vert. v. ; 



2de edit. v. 549. Risso, VEurop. Merid. iv. 416? 

 Nereilepa lobulata, Blainv. Diet. Ivii. 469. 

 Nereis lobulata, Aud. ^ M.-Edw. Litt. de la Franee, ii. 191. pi. 4 a. 



f. 7, 8. Grube, Fam. Annel. 50. 

 Nereis littoralis. Leach, MSS. Brit. Mus. 



Hab. The littoral region ? 



Besc. Body plano-convex, linear, narrowed at the head and pos- 

 teriorly, of numerous narrow and similar segments. Head trans- 

 versely oblong, with four large eyes, of which the posterior pair are 

 higher than the anterior. Antennae nearly as long as the large 

 palpi. Tentacidar cirri unequal, one-half longer than the diameter 

 of the body. Proboscis surrounded at the base with a double circle 

 of dark-brown prickles interrupted above, where there are two 

 stronger and solitary ones, with a group of small ones between. 

 Post-occipital segment one-half longer than the second, distinctly sinu- 



