184 LINETTS MARINUS. 



yards were measured without rupture, audyet the mass was not half uncoiled. It chiefly delights 

 to lurk under stones not far from low- water mark, or in tidal pools, and is occasionally found 

 looped like a living string of caoutchouc amongst the seaweeds fringing the sides of the latter. 

 It is useless in such a case to attempt to capture the worm by pulling at the free end, for, 

 although it resists considerable tension, rupture is apt to follow : it should be allowed to 

 contract itself, and then lifted or rolled in a mass into the vessel. At first sight it seems strange 

 that nature should have fashioned an animal so soft and apparently so helpless as this, devoid 

 of arms either of offence or defence throughout its extreme length, and which, moreover, 

 can be so easily ruptured. Yet the facility with which reproduction can take place in wounded 

 examples on the one hand, and the shelter afforded by its site on the other, give it sufficient 

 protection in the struggle for existence as an adult form, while the enormous powers of increase 

 in the ordinary way by ova render the continuance of the species doubly secure. 



There is something remarkable in the movements of a large specimen of this huge worm, 

 as its quivering body emerges from a dark creek in one of the little caverns that abound amongst 

 the tidal rocks. No useless bustle warns its companions of its approach, but it glides 

 silently forward with its exploratory snout, and scatters the smaller inhabitants by the very 

 stealth and suddenness of its appearance. Some may even be excused in reckoning it the evil 

 genius of the pool — dark, slimy and mysterious, moving hither and thither, as it were, by an 

 invisible^agency, and whose ways, like the inextricable knots and coils of its serpentiform body, 

 are difficult to find out. It is not to be more harshly judged, however, than the young Cotti, 

 Shannies, and Cyclojpteri, that shelter themselves from its approach amidst the blades of the trailing 

 tangles, the Hippolytes and Mysidce that reconnoitre it from under the fringes of Corallina, 

 Ulva and Cramium, the Idoteidce and Caprellidce that climb monkey-like on their branches, 

 or than the sluggish Doris adherent to the variously tinted Halichondria. All are equally pre- 

 datory, and subserve the special ends for which they live ; and if the elongated worm preys 

 by stealth and not by swift and open attack, this is due to its physical constitution, and not 

 to any acquired vice or degradation. If it swallows its prey alive, it is, at any rate, devoid of 

 instruments of laceration or torture, such as the jaws of its higher allies or the thread-cells of the 

 Hydrozoa. 



Z. marinus lives well in confinement, and, without receiving any food, will survive for 

 years, though the body greatly diminishes in size, both as regards length and thickness. Indeed, 

 as in other examples, the insensible consumption of the formed tissues supports the animal under 

 circumstances so abnormal, for we cannot place any weight upon food derived from microscopic 

 organisms in so limited a supply of salt water, and one so rarely or never changed. Sickly 

 specimens die from behind forward piece by piece, a fresh portion being thrown off at intervals 

 until the head is reached. It is fond of taking refuge in tubes ; thus a small one captured at Herm 

 thrust out the rightful owner (a Protula), coiled itself therein, and is now preserved in situ. 

 Several have also been found with the body looped through a broken Trochus or Littorina, which 

 formed a kind of anchor in the runlets of sea-water in which their protecting stones lay. 

 Not only do some fragmentary specimens, when put in spirit, turn themselves inside out, as Sir J. 

 Dalyell saw in the living animal in salt water, but more than once I have been puzzled when 

 making transverse sections by finding one part of the body doubled quite within the other, and 

 this for a considerable distance. The entire skin gives a marked acid reaction to test-paper. 



The breeding season would seem to be in June, but spermatozoa have been found fully 



