436 



WORMS. 



they are found ; those living in clean sand being of a light tint, whereas black 

 specimens frequent slimy sand, strongly impregnated with decaying organic matter. 

 The segments of the body are not all alike ; those at the front end being 

 furnished with a few small, widely -separated tufts of bristles arranged in 

 pairs; then follows a series in which the clusters of bristles are large, bush-like, 

 and close together; while the end of the body is cylindrical and without bristles 

 and parapodia. The goblet - shaped organ, shown in the illustration, projecting 

 from the head is the protruded proboscis. This worm, which is found on all 

 the coasts of Europe, is used by fishermen as bait. At low water, on some sandy 

 shores, it may be found in vast numbers. 



In the family Clymenidce, to which belongs the worm known as Arenia 

 tragilis, the body is only divisible into two regions. The fore-part, which is of a 

 dirty red tint, alters its shape greatly owing to the retraction and extension of its 



Arenia frag His (nat. size). 



segments ; while the exceedingly long and slender hinder part is of a yellowish 

 colour. A remarkable family is that of the Chcvtopteridcv, containing the genus 

 Olicetopterus, of which a specimen is represented of the natural size in the illustra- 

 tion on p 437. The head is funnel-shaped, with an indentation on its upper side, 

 and from this spring a pair of feelers. The body is marked out into three regions ; 

 the most striking being the formation of the five segments which compose the 

 middle region of the body. From the first segment of this area the parapodia 

 stand out like a pair of flat feelers, while the lower branches of these 

 feet are spread like a ruff over the abdominal region. The upper branches of 

 the parapodia of the second segment unite with those of the first to form a 

 dorsal crest, and between these and the lower branches the skin is much swollen 

 and of a violet colour : the following; three segments are swollen and have 

 relatively short parapodia. Species of these worms are found on the coasts of 

 Normandy and in the Mediterranean. Like many other marine animals, this 

 worm is phosphorescent, the phosphoric matter spreading like a cloud in the water. 

 In the next group the gills are in the form of small trees or branches of 

 threads attached to the end of the head ; while the mouth is unprovided with 

 cither teeth or a proboscis. The creatures spend their days in tubes, from 

 which they can only be extracted by force. In Hermella the body ends in 

 a long unjointed, limbless, hairless tail, while the rest of the body bears well- 



