THE ANATOMY OF SCALIBREGMA INFLATUM. 295 



poned until I had been able to examine many more speci- 

 mens of some of the species therein mentioned. There 

 seems little prospect of obtaining further material for some 

 considerable time, and I have therefore appended the table, 

 although it cannot be regarded as a final one, as it is defi- 

 cient in several respects. It is based largely on the results 

 recorded in the former part of this paper, supplemented by 

 the diagnosis of the authors responsible for the various 

 species. 



The Scalibregmidee form a moderately compact family, the 

 characters of which may be thus stated. 



SCALIBEEGMID^. 



Limnivorous Polychteta, arenicoliform or maggot-like in 

 shape. Gills, if present, confined to the first five (or six, 

 according to Johnston) segments. Prostomium small, in 

 some drawn out at its antero-lateral angles into short pro- 

 cesses ; in others its two lobes are blunt and rounded ; 

 bordered laterally by the two nuchal grooves through which 

 the eversible nuchal organs may be protruded. 



Parapodia consist of almost identical notopodia and neuro- 

 podia, each bearing setae of two kinds, viz. simple capillary 

 setae, and furcate set^ with unequal, barbuled, pointed limbs. 

 Between the two rami of each parapodium there is in most 

 species a small sense organ, which may be withdrawn into a 

 shallow depression of the epidermis. The segments are sub- 

 divided into annuli, and the skin, especially in the anterior 

 part of the body, is usually raised into squarish or oval eleva- 

 tions. Internally there are four transverse diaphragms 

 situated at the posterior end of the first, second, third, and 

 fourth chietigerous segments. The eversible pharynx is 

 smooth, there being no armature whatever. The heart is 

 median and is an enlargement of the dorsal vessel. There is 

 a pair of nephridia in each segment except in a few of the 

 anterior ones. Each nephridium is a narrow ciliated tube, 



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