437 



ratteri secondari, per la speciale loro conformazione esterna, riguardante 

 soprattutto la forma depressa, il grande sviluppo della suola pedale, la 

 ristretta cavità pleuropodiale dell' una, e la forma rigonfia, la rudi- 

 mentazione della suola pedale, e l'ampia cavità pleuropodiale dell' altro: 

 dipendenti probabilmente, come ne espressi l'idea nel 1893, da un 

 maggiore adattamento dell' una a strisciare, dell' altro a nuotare a mo' 

 dei Cefalopodi. 



Queste le conclusioni a cui sembra si possa pervenire, per ora, sui 

 pochi dati anatomici che si hanno sul gen. Phyllaplysia^ nella speranza 

 che fra breve nuove ricerche, fondate su copioso materiale, possano 

 gettare maggior luce suU' argomento. 



Milano, Museo Civico di Storia Naturale, 8 maggio 1901. 



4. Phylogenetic Relationship between Amphineura and Cephalopoda. 



By J. Graham Kerr, Cambridge. 



eingeg. 15. Mai 1901. 



In the last number of Spengel's Zool. Jahrbücher (Supplement V. 

 Band 2. Heft 2) which has just reached Cambridge, Prof. Dr. L. Plate 

 publishes the concluding portion of his admirable work upon the 

 anatomy of the chitons, marking the completion of a work upon which 

 I feel sure older and better known Zoologists will congratulate Prof, 

 Plate as heartily as I do myself. 



Pages 559 — 561^ I find devoted to destructive criticism of what 

 purport to be views expressed by me as to the genetic relationship 

 between the Amphineura and Cephalopoda, but which through some 

 unfortunate misapprehension so completely misrepresents my view 

 upon Avhat is an important morphological question that I feel bound 

 to correct it at once. 



I am in fact made by Prof. Plate to express the belief that the 

 Cephalopods are descended from ancestors resembling Chitons. 



Now at the time when I wrote the paper under review'^ I held 

 most strongly, as I hold still, that it is quite unjustifiable to attempt 

 to derive any living group of animals from any other living group. 

 Such an attempt involves necessarily the view that the supposed 

 ancestral group has remained completely unaffected by all evolution- 

 producing agencies through vast periods of time — from the epoch 

 Avhen the younger group split off from it until the present time. 



1 cf. also on p. 583. : »Ebenso wenig können die Cephalopoden, wie Kerr und 

 Haller wollen, als ein Seitenzweig chitonartiger Vorfahren aufgefaßt werden.« 



2 On some points in the anatomy of Nautilus pompilius. Proc. Zool. Soc. 

 1895. p. 664. 



