242 



KNOWLEDGE 



[November 1, 1899. 



the myxies an instance of the close association of death 

 with reproduction ; and we are reminded of the analogous 

 cases of the mayfly and the butterfly, which die after 

 laying their eggs, and of the death of the male bee after 

 pairing. 



The other view of the facts to which we have referred is 

 that the throwing off of the sporangium and the capillitium, 

 and the shells of the spores, is not the death of the whole 

 parent organism, but the partial death only which occurs 

 when the parts which have become useless are cast o£f 

 and allowed to die, and in this view there is in the cycle 

 of the myxie's life neither death nor generation, but an 

 everlasting life ; the same protoplasm would be thought 

 of as going on in an eternal round of life, subject only to 

 accretions and to losses. True it would be that the shell 

 of the spore, the coats and foot of the sporangium, and 

 the capillitium which it contains, have been thrown aside 

 and perish ; but the residue of the protoplasm seems to 

 pass from swarm spores into plasmodium, from Plas- 

 modium to swarm spores, and so on in a perpetual round. 

 The swarm spores thus appear not as emanations from 

 the parent but as the parent itself, and the new generation 

 and the old are but one person (if personality may here 

 be spoken of). If we think of death we search without 

 success for the moment of its occurrence, and we look in 

 vain for the dead body. 



Whether of these two views be the more reasonable it 

 may be hard to decide. However that may be, it is certain 

 that there are unicellular bodies, such as the Diatoms, in 

 respect of which Weismann has so forcibly shown that 

 death cannot be thought of as a normal event. Thus out 

 of the depths and first rudiments of organic life there 

 crops up a suggestion of that immortality which is the 

 hope and aspiration of its very highest members. 



Then with regard to encystment. We have seen that 

 this occurs in two forms in the life-history of the myxies. 

 We have found that the single swarm spore may be encysted 

 and is then known as a microcyst, and that from this 

 condition it may be awakened and recalled to its activity 

 as a swarm spore, and we have found also that, in the form 

 of sclerotium, the whole plasmodium may become quite 

 dry and hard as an aggregation of cysts, and thus be 

 reduced to a condition of suspended vitality, but from this 

 also it may be aroused to its former powers of movement 

 and life as a plasmodium. In neither of these cases do we 

 find encystment to be associated with death, nor with 

 reproduction. " The essential characteristic of encyst- 

 ment," says Weismann, " is a simple process of rejuvenes- 

 cence without multiplication." 



The length of time during which animation can be sus- 

 pended in the case of plasmodia is very remarkable. De 

 Bary found a plasmodium of Didymhvm ser/mla to move 

 after seven months' desiccation ; and a case is cited by 

 him of a plasmodium which after twenty-five years' 

 residence in an herbarium began, after four or five days' 

 immersion in water, to develop as a beautiful network. 



Relations of the Group. — The proper position of the 

 myxies in the world of organized beings is a subject on 

 which there has been and still is a great diiference of 

 opinion. So profound is the difficulty of the question 

 whether they are animals or vegetables that one of the 

 most careful students of their nature has declared that 

 its solution " depends rather on the general philosophic 

 position of the observer than on facts." 



Those authors who place the myxies in the animal 

 kingdom have generally attached most importance to the 

 swarm spore and plasmodium stages of their existence, 

 and have insisted on their likeness to the protozoa ; the 

 advocates of their vegetable character have mainlv dwelt 



on their method of reproduction — on their sporangia and 

 their spores. 



But even assuming them to be vegetables, there remains 

 the question where they are to take their place in that 

 realm of Nature. They were placed among the fungi by 

 Fries, but with a lively consciousness of how entirely they 

 differed from all the other members of the class. ' ' Vegetatio 

 maxime singularis et a reliquorum fungorum prorsus 

 diversa," he says of this group. The fungi seem as a 

 natural group to be well characterized by a prothallus 

 constituted of hyphfe — generally multicellular — whereas 

 the myxies are represented in that stage by the strange 

 Plasmodium of which we have said so much. 



Attempts have been made to show that difi'erent sections 

 of the myxies correspond with different sections of fungi ; 

 the common myxies being treated as of the Gasteromycetic 

 type ; the IHctyustelhm as of the Mucorine type ; and, 

 according to some writers, the Ceratomyxa mucida as of 

 the Hydnum type and the Ceratomyxa porioides of the 

 Polyporus type ; and from this supposed correspondence 

 of type it has been suggested as probable that other types 

 of fungi will be found to be represented amongst myxies, 

 and that so we shall have two parallel series of fungi ; the 

 difference in each case being that the one is characterized 

 by a mycelium of hyphse, and the other by a plasmodium. 

 This view appears to us to be fanciful, and to slur the 

 really broad line of distinction between fungi and myxies. 

 More rational would seem to be the view put forward by 

 one of the latest writers on classification, who has formed 

 of these little organisms one of the four primary divisions of 

 the vegetable kingdom, and made for them a place of equal 

 rank with the whole of the phanerogamous plants ; so 

 distinct a position scarcely seems excessive to mark the 

 singularity of their structure and life-history. In fact, 

 one of the many interesting points about this group of 

 organisms is the extent to which they stand alone ; the 

 difficulty of finding any other creatures to which they 

 stand in the relation either of descendants or ancestors. 

 "The mycetozoa," says De Bary, "show only a slight 

 agreement, either in the general course of their develop- 

 ment, or in the characteristic features of its separate stages, 

 with organisms which are of undoubted vegetable origin, 

 whether they be fungi or plants other than fungi ; the 

 agreement, with the exception of the few cases in which 

 cellulose makes its appearance, is common to phenomena 

 which are common to all organised bodies." 



We are much impressed with the notion that the position 

 of the myxie will be found to vary according as the one or 

 the other stage of their existence is held to have the 

 highest classificatory value. We therefore propose to 

 consider what relations they exhibit in these various stages 

 of their life-history. 



SHELLS AS ORNAMENTS, IMPLEMENTS, 

 AND ARTICLES OF TRADE. 



By E. Lydekker. 



FROM the intrinsic beauty of their form and colora- 

 tion, coupled with their almost imperishable 

 nature, the shells of numerous kinds of molluscs 

 have been employed from the earliest times by 

 aboriginal tribes in all parts of the world as 

 articles of personal adornment. Others, again, are suitable 

 as implements for culinary and kindred purposes ; while a 

 few have been selected as convenient media for exchange. 

 Not only are entire shells, either singly or strung together, 

 employed as personal decorations, but in many instances 

 the shells are cut or ground, either into bangles, or into 



