284 



ANNELIDA 



Key to the families of Nereidiformia here described: 

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

 a z Back without these scales. 1 * ^PHBODITIDAE 

 &! Dorsal cirri broad and leaf-like, overlapping one another, but not cover- 

 ing the back 2. PHYLLODOCIDAE 



6 2 Cirri not broad and leaf-like. 



Cx Dorsal cirri usually long and slender; asexual budding usual. .3. SYLLIDAE 

 c 2 Dorsal cirri not very long ; asexual reproduction unusual, 

 dj Prostomium not annulated. 

 1 No large teeth or jaws on proboscis. 



/! Proboscis simple; parapodia usually uniramous 4. HESIONIDAE 



/ 2 Proboscis divided into lobes ; prostomium small and acute. .9. AKICIIDAE 

 e t Two or more large teeth or jaws usually on proboscis. 

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



peristomial cirri 5. NEREIDAE 



/ 2 Two or more pairs of jaws. 



Oi One pair of dorsal and 1 pair of ventral jaws 6. NEPHTHYDIDAE 



g a Jaws form a complicated apparatus 7. LEODICIDAE 



di Prostomium annulated ; tentacles inconspicuous ; proboscis very large. 



8. GLYCEBIDAE 



FAMILY 1. APHRODITIDAE. (FiG. 452, A.) 



Worms 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: 

 numerous genera and species. 



Key to the genera of Aphroditidae described : 



a x Body with felt-like bristles on sides and back 



concealing the elytra 1. APHRODITA 



a 2 Body without this felt. 

 &! Body with but few pairs of elytra. 

 c x Prostomium prolonged into the base of the 

 lateral tentacles ; 12 pairs of elytra. 



2. LEPIDONOTUS 



c 2 Prostomium produced forward into a pair 

 of pointed tips, quite free from the base 



of the tentacles 3. HABMOTHOE 



& 2 Body with numerous pairs of elytra. 



Ci Over 40 pairs present 4. PHOLOE 



c 2 Over 100 pairs present 5. STHENELAIS 



- i V'A ' '* ' if'/ 1 > -i 



Fig. 453 

 Aphrodita hastata (Moore). 



1. APHRODITA L. Body elliptical, with 15 

 pairs of elytra; entire back covered by the 

 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, 

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



