232 



NATURAL HISTORY. 



is brilliant in colour, with flesh and iridescent blue tints. It is a great wanderer, burrowing often 

 in the mud in brackish water marshes and pure sea-water shores. In its larval state, just after the 

 tentacles are developed, it is phosphorescent, and may be seen on the shells of oysters. 



The White-rag Worm*, or Lurg, is common on the British shores, and varies from six to ten 

 inches in length, being about three-tenths of an inch wide. It is of a beautiful peai-ly lustre, 

 and the feet are much developed, and increase gradually in size from the head to about the middle 

 of the body, and then decrease. It lives in the sand, burrowing into it by means of its strong 



LURG (Neplithys cceca). 



proboscis, and holding itself fixed by its setigerous feet. When swimming it uses the feet as oars, 

 and moves very quickly through the water. Fresh water soon produces convulsions and death. 



A Worm called the Prolific Syllist belongs to the family Syllidse. It has the head distinctly 

 seen, and the tentacles are pointed, and the creature has eyes. Dr. Johnston observed that 

 this Syllis is more studious to divide than to unite. When it divides, the posterior half 

 grows a head before it is separated, so that the Worm looks like two individuals joined 

 together, the one holding on to the hinder extremity of the other. Quatrefages has 

 shown that although the two halves are alike when separated, yet they have very different 

 internal structures and gifts. The anterior half continues to eat as before, and conducts itself 

 as an independent creature ; but the other individual is devoted to the reproduction of the species, 

 and does not eat. In another allied form, the posterior half becomes self -divided into as many as 

 six parts, each acquiring the cephalic appendages before dividing, and thus the Worm wanders about 

 for a while, with a train of six mothers crammed with ova formed of its own tail. These separate, 

 and die in giving birth to their ova. 



The family of Leaf-bearing Worms, the Phyllodocidse, contains very beautiful Worms, which are 

 easily distinguished from all the other Annelids. They are usually of a linear, elongated figure, 

 and the body is furnished with a series of foliaceous lamellse 011 each side, somewhat resembling 



elytra. They form a border, originating im- 

 mediately above the insertions of the feet, and 

 are in reality the cirri metamorphosed into leaf- 

 like appendages. These structures are supposed 

 to be useful for respiration ; but, in addition to 

 this, they are equally useful as organs of loco- 

 motion, for, as they follow the motions of the 

 feet, and are capable of being partially altered 

 from a horizontal to a perpendicular position, 

 "they act as a bank of oars, and must be 

 especially useful when the Worm glides from a 

 solid surface, and finds itself unsupported in the 



PHYLLODOCE KIXliEKGlI. 



water. Hence the species are quick and lively, 

 and swim with considerable ease." The Phyllodocidse are provided with a very large proboscis, 

 the under side of which is roughened with rows of fleshy papillae. The one-branched feet, 

 independent of their leaf-like appendages, are rather small, and the setse, which spring from 

 them, and of which there is only one brush, are slender and elegant in shape. 



The genus Myxostomum contains little discoid parasites covered with vibratile cilia, and 

 they have four pairs of suckers on the sides of the belly. They have a proboscis and five pairs of 



* Nephthys cccca. f Syllis prolifera. 



