POLYCHAETE WORMS, PART 1 



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pale red, reddish yellow, with red middorsal blood vessel and red to 

 red-brown branchiae. 



Biology. — Found burrowing in bottoms of sand, muddy sand, and 

 sandy mud. They may be gregarious, since they are found in large 

 numbers in restricted areas, and may be associated with the closely 

 related S. robustus, the latter getting to be considerably larger in 

 size. According to Moore (ms.), they are found in pure sand, where 



Figure 76. — Orbiniidae, a-J, Scoloplos fragtlis: a, dorsal view thoracic region and first few- 

 abdominal segments; b, dorsal view posterior end; c, dorsal view anterior end; d, lateral 

 view anterior end with proboscis extended; e, thoracic parapodium, posterior view; /, ab- 

 dominal parapodium, posterior view, g, Scoloplos robustus, abdominal parapodium, 

 posterior view, h-i, Scoloplos armiger (after Okuda, 1937b): h, transitional parapodium 

 from setiger IS; t, crotchet-like neuroseta. 



