NATURE 



36; 



THURSDAY, AUGUST 18, 1892. 



A DEBATABLE LAND—PLANTS OR 

 ANIMALS? 



A Monograph 0/ the Myxogastres. By George Massee. 

 (London : Methuen and Co., 1892,) 



THIS work is much in advance of any book in the 

 English language treating of the perplexing group 

 of organisms that forms its subject. The author has been 

 in peculiarly favourable circumstances for the prepara- 

 tion of such a monograph, having enjoyed full access to 

 "the splendid collection of Myxogastres in the Royal 

 Herbarium, Kew, rich in types, and with numerous annota- 

 tions by Rostafinski," as well as had "the loan or gift of 

 valuable, and in some instances unique, specimens " from 

 other workers in the same field in different countries. 

 He has fully acquainted himself with the literature of the 

 subject, and has made many personal observations on 

 the structure, and, in some cases, on the life-history, of 

 various types. He is thus able to bring to bear on the 

 discussion of the problems that claim consideration 

 a wide and varied knowledge ; with the result that 

 the book is indispensable to every student of the 

 Myxogastres. The introductory portion will be found 

 worth perusal by others besides specialists, as it dis- 

 cusses the arguments for and against the vegetable 

 nature of the group. While accepting the view that the 

 origin of the Myxogastres is to be found among the 

 Flagellatce, he comes to the conclusion that the sum of 

 the characters presented by them in the reproductive 

 phase manifests a tendency " in the direction of the 

 vegetable kingdom, and more especially in the direction 

 of the Fungi." But he is unable to establish strict 

 homologies with the latter ; since the Myxogastres are 

 " a terminal group, and permit no comparisons with 

 higher forms of the same type." In the discussion of 

 this vexed question, Mr. Massee shows none of the 

 virulence to which it has given rise in former times ; and 

 he endeavours to do justice in his statement to the views 

 of De Bary, and of other supporters of the view that the 

 organisms in question should be regarded as animals. 

 After all, to an evolutionist at least, the distinction would 

 appear more of verbal than of real importance. 



Accepting the view that there are certain forms, of a 

 very primitive structure, from which the animal and 

 vegetable kingdoms have been developed in ever-increas- 

 ing specialization, there is cause to expect the existence 

 of more or less intermediate types, in which the characters 

 at one period of their life-history are more those of 

 animals, and at another period more plant-like. It 

 matters little under which kingdom we agree to place 

 them. Here, as elsewhere. Nature refuses to be bound 

 down by rigid classification, and we must accept facts as 

 they are, not as any a priori system might wish to make 

 them. That the Myxogastres are not Fungi may be 

 admitted ; though they show a considerable similarity in 

 various points in the course of development — a similarity 

 clearly stated by Mr. Massee in his discussion of the 

 whole question. 



The term Myxogastres is employed, we infer, on the 

 ground of priority. It possesses, however, the incidental 

 NO. I I 90, VOL. 46] 



advantage of not implying any positive view on the nature 

 of the group, in the same way as do the terms Myxo- 

 mycetes and Mycetozoa. The limits of the group are taken 

 in this monograph in the sense employed by Rostafinski. 

 It thus does not include the Acrasiece and Ceraiium, ad- 

 mitted as Mycetozoa by De Bary ; nor does it make any 

 reference to the numerous forms of the Monadinecz, which 

 Zopf discusses in his " Schleimpilze " in Schenck's " Hand- 

 buch der Botanik." Thus limited, the group is more 

 homogeneous ; though the definition is, perhaps, some 

 what arbitrary, and omits forms that are undoubtedly 

 related to the more specialized types, and an English 

 work on which would be welcome. 



The author enters on somewhat slippery ground in the 

 endeavour to explain the line of development of the 

 Myxogastres, and also to illustrate his ideas of the 

 relationship between the several orders. He holds that 

 four orders can be distinguished by the presence or 

 absence of lime in the sporangial wall, and by the pre- 

 sence and nature of the capillitium. 



" In each order we find the special characteristic idea 

 evolving through a sequence of genera, the terminal one 

 not connected with any higher order, hence the special 

 feature terminates abruptly within the order where it 

 originated, and it is invariably in some comparatively 

 undifferentiated genus near the initial point of each 

 order, that we meet with the suggestion of a new line of 

 evolution, which, at its maximum of development, con- 

 stitutes the characteristic feature of the order immediately 

 in advance of the one from which it emanated in an 

 incipient condition." 



Turning now to the systematic portion of the work, we 

 find that it gives abundant proofs of care and of familiarity 

 with the several forms, based on personal examination of 

 each. The method of description is clear, the more 

 important characters being printed in italics. Mr. Massee 

 recognizes fully the difficulties of determining the limits 

 of species and of the larger groups " while the lif^ 

 history of the majority of forms is still unknown," saying 

 plainly that 



"all attempts at classification, as also the conception 

 as to what constitutes a species, must be considered as 

 tentative. When we are better acquainted with the main 

 lines of development and lines of variation, also the con- 

 ditions determining these variations, it is certain that the 

 main factor in the discrimination of species will not be a 

 one-twelfth oil-immersion objective." 



Basing his acquaintance with the Myxogastres on per- 

 sonal examination of large numbers of examples, fresh 

 and dried, many of the latter being authentic types, 

 Mr. Massee does not hesitate to unite species and genera 

 hitherto kept as distinct, but shown to be connected by 

 fuller material. Thus several familiar names become 

 sunk as synonyms; eg. Licea, Schrad., and Lindbladia, Fr., 

 are ranked under Tubulina, Pers. (emended). Under the 

 generally accepted rules of nomenclature, this leads to 

 Massee standing as the authority for many species, trans- 

 ferred by him, in reality, to another genus. But, besides 

 such cases of apparent novelties, there are also a good 

 many descriptions of neio species in the usual sense of 

 the term. The synonyms are carefully given under each 

 group and species. A wise reticence has been observed 

 in the endeavour to recognize the species meant by most 

 of the older writers who mention the Myxogastres. The 



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