144 PACKARD—CLASSIFICATION OF ARTHROPODA. [April 3 
which Peripatus arose, with two lines of descent, one ending in 
the Chilopoda and Insecta, the other in Diplopoda, Pauropoda and 
Symphyla, the branch finally ending in the Arachnoidea. He thus 
divides the Arthropoda into Branchiata (Crustacea) and Tracheata. 
He quotes Plate,’ who in 1889 considered that Crustacea and the 
Tracheates followed each an ‘‘entirely separate developmental 
path,’’ since he derived the Crustacea from the Rotatoria, and the 
Tracheata from the Annelida. 
In 1883 Kingsley’ inquired whether the group Arthropoda is a 
natural one, calling attention to the fact that the insects have been. 
derived from Peripatus, while the Crustacea ‘‘had an ancestor 
resembling the Nauplius of the Phyllopoda or the Copepoda.’’ In 
1894* he divided the Arthropoda into three subphyla: I. Bran- 
chiata; II. Insecta or Antennata, and III. Diplopoda, rejecting 
the old grouping into Branchiates and Tracheates (though retain- 
ing the Branchiata), and he states his belief that the three divisions 
he makes ‘‘ are but remotely related to one another, and it may yet 
be proved that they have no common ancestor nearer than the 
Annelids.”’, * 
Indeed, as early as 1886, A. C. Oudemans* thus expressed his 
views as to the relations of Limulus with the trilobites, and of the 
derivation of the scorpion from the Eurypterida: ‘‘ Though some 
zoologists doubt the relationship of Limulus with the Trilobita, the 
Paleontologists have long ago been convinced of it. Among the 
numberless Trilobita there occur all possible transition forms be- 
tween them and Limulus, and to Scorpio the .Eurypterida form a 
partial bridge.’’ His genealogical tree represents the Xiphosura as _ 
originating from the trilobites and the scorpions as derived from 
the Eurypterida, in this respect theoretically anticipating the results 
attained by Pocock with Paleophonus. Oudemans also acknowl- 
edges the close resemblance of trilobite larve to that of Limulus. 
1« Ueber die Rotatorien fauna des bottnischen Meerbusens, nebst Beitragen 
zur Kenntniss der Anatomie der Philodiniden und der systematischen Stellung 
der Raderthiere” (Zeztschrift f. Wissen. Zoologie, xlix, December, 1889). 
2 American Naturalist, xvii, p. 1034, 1883. 
3 American Naturalist, xxviii, pp. 118 and 220, 1894. 
4« Die gegenseitige Verwandschaft, Abstammung und Classification der so” 
gennanten Arthropoden” (Zijdschr. d. Nederland. Dierk. Vereen, 2° Ser. 
Deel 1, 1886). 
] 
