COLLECTING AND PRESERVATION 



Freshwater species are collected in much the same manner as marine forms. 

 Those from shore areas and shallow water are collected with a shovel and 

 a fine sieve. The sediment is placed in the sieve, washed through and 

 the remaining animals then removed. Those from deeper water may be col- 

 lected by dredging or by the use of grab samplers the sediment from which 

 is then washed through a fine sieve. 



Polychaetes should be initially preserved in 10% formalin and subsequent- 

 ly transferred to 70% ethyl alcohol. As usual, whenever possible obser- 

 vations should be made on the living animal noting such things as color- 

 ation, presence of eyes etc. as these may possibly change or disappear in 

 the preservatives. 



IDENTIFICATION 



Essentials for identification are a dissecting microscope, compound micro- 

 scope, micro-dissecting scissors, micro-forceps, slides and cover slips. 

 In some instances, fine needles are beneficial. Glycerin serves as a 

 satifactory temporary mounting medium and glycerin jelly for more perman- 

 ent mounts. If the setae and/or parapodia need to be examined, the para- 

 podia should be removed and viewed on a slide under the compound micro- 

 scope. 



The following is a discussion of characters used in the identification of 

 North American species. A nereid is a typical errant polychaete with a 

 well developed prostomium, sensory appendages and often with eyes (Fig. 

 la). The parapodia are also well developed and may be uniramous (Fig. lb) 

 with one setigerous lobe or biramous (Fig. Ic) with two lobes. In bira- 

 mous parapodia the dorsal lobe is the notopodium and the ventral lobe the 

 neuropodium with the various subdivisions of these lobes referred to as 

 ligules (see Fig. Ic) . The term setiger refers to any setae-bearing 

 segment. Nereids possess an eversible pharynx armed with jaws and coni- 

 cal projections called paragnaths (see Fig. Ic) . The pharynx may also 

 be smooth or bear soft papillae. The arrangement of these paragnaths 

 and papillae is characteristic for each species and the pharynx is divid- 

 ed into two rings, the oral ring surrounding the mouth and the maxillary 

 ring where the jaws are inserted. These two rings are in turn subdivid- 

 ed into areas where the paragnaths are located. The areas are designated 

 by Roman numerals (Fig. Id) . Setae are compound spinigers with thin, 

 tapering blades or falcigers with short blunt blades (Fig. le, f ) . In 

 the Sabellidae and Serpulidae, which are sedentary forms, the body is 

 divided into two regions with pronounced differences in the parapodia 

 and setae. Parapodia are reduced and not elaborately developed as in 

 the nereids. The setae are simple capillaries and hooks (Fig. Ig-j). 

 The anterior end is modified to form a branchial plume or crown which is 

 used for food getting and respiration (Fig. 2). 



