284 ANNELIDA 



Key to the families of Nereidiformia here described: 

 iiy Back partially or totally covered with broad, overlapping scales. 

 «, Back without these scales. 1- AphRODITIdae 

 by Dorsal cirri broad and leaf-like, overlapi)ing one another, but not cover- 

 ing tht' back 2. Pii yllodocidae 



1)2 Cirri not broad and leaf-like, 

 c'l Dorsal cirri usually long and slender; asexual budding usual. .3. Syllidae 

 c. Dorsal cirri not very long ; asexual reproduction unusual, 

 rfi Prostomium not annulated. 

 Ci No large teeth or jaws on proboscis. 



/i Proboscis simple; parapodia usually uniramous ..4. Hesionidae 



/a Proboscis divided into lobes ; prostomium small and acute. .9. Ariciidae 

 €2 Two or more large teeth or jaws usually on proboscis. 

 A But 1 pair of jaws ; 1 pair of tentacles, 1 pair palps and 4 pairs 



peristomial cirri 5. Nereidae 



/a Two or more pairs of jaws. 



g^ One pair of dorsal and 1 pair of ventral jaws 6. Nephthydidae 



02 Jaws form a complicated apparatus 7. Leodicidae 



(Zi Prostomium annulated ; tentacles inconspicuous ; proboscis very large. 



8. Glyceridae 



Family 1. APHEODITIDAE. (Fig. 452, A.) 



Woniis with imbricated scales (elytra) on the back, mostly on alter- 

 nate segments, which may take the place of dorsal cirri; slender dorsal 



cirri usually alternate with the scales; head 

 with usually 3 tentacles and 2 long palps: 

 "*r'Tf¥W numerous genera and species. 



'h'^/^-SJSL Key to the genera of Aphroditidae described : 



tti Body with felt-like bristles on sides and back 



^^''liTWiami concealing the elytra 1. Aphrodita 



02 Body without this felt. 

 6i Body with but few pairs of elytra. 

 Ci Prostomium prolonged into the base of the 

 lateral tentacles ; 12 pairs of elytra. 

 '* * 2. Lepidonotus 



^vfrxM^HT ^2 Prostomium produced forward into a pair 



of pointed tips, quite free from the base 



of the tentacles 3. HARMOXnop: 



»?*»'Avaf^^Bg ^^2 Body with numerous pairs of elytra. 



^TTwinir ^1 Over 40 pairs present 4. Pholoe 



C2 Over 100 pairs present 5. Sthenelais 



1. Aphrodita L. Body elliptical, with 15 

 , , ^., ^^}^-^'^'f' ,,^ , pairs of elytra; entire back covered by the 



Aphrodita fiastata (Moore). r- ^ ? J 



long felt-like setae arising from the notopo- 

 dium; strong dorsal setae also present, projecting through the felt; 1 

 short tentacle and 2 long palps on the head: about 15 species, 2 in the 

 Woods Hole region. 



A. hastata Moore (Fig. 453). The Sea Mouse. Body short, wide, 

 eiid thick, the sides and back covered with the iridescent felt; dorsal 



