THE ANATOMY OF SCALIBREGMA INFLATUM. 297 



podium is composed of two simple rounded elevations, in 

 which the set^e are lodged. 



3. Sclerocheil us. — Two triangular masses of pigment 

 on the prostomium. Strongs curved, acicular sette are found 

 in the first chastigerous segment. The parapodia in the 

 posterior segments of the animal bear ventral cirri. Four 

 anal cirri present. 



S. miuutus, Grube. 



4. A sclerocheil us. — Pigment masses absent. Curved 

 acicular setae finer than those of Sclerocheil us are present 

 in the first three cha^tigerous segments. No ventral cirri. 



A. intermedins. (Lipobranchins interme- 

 dins, S. Joseph.) 

 II. Body of animal maggot-shaped. Prostomium dis- 

 tinctly divided anteriorly into two by a median groove ; each 

 half of the head is blunt and rounded ; there are no tenta- 

 cular processes. The parapodia do not form projecting 

 lamellae, and do not bear cirri. Each parapodium is com- 

 posed of two simple rounded elevations which arise sepa- 

 rately from the body-wall. Anal cirri absent. 



5. Eumenia. — Four (or six) pairs of gills present on 

 chaetigerous segments 2 — 5 (or on the first six according to 

 Johnston). 



E. crass a. Oersted. 



6. Lipobranchins. — Gills absent. 



L. jeffreysii, Cunningham and Ramage. (Eu- 

 menia jef f reysii, Mcintosh.) 



20. Affinities of the Scalibregmid^. 



The Scalibregmidte, as references in the previous portion 

 of this paper have shown, resemble the Arenicolidse in many 

 of their structural features, and they also agree in some 

 points with the Opheliidae. These three families have several 

 points in common, as they are limuivorous, and present 

 certain of the peculiarities characteristic of such Polychaetes, 



