348 Br. H. Woodarird — On Ajjti/clius and Apt/jchojjsis, — 



covering the entire surface of their carapaces ; yet Herr Dames has 

 evidently no doubt that these forms are related to Nebalia, which has 

 a smooth carapace destitute of ornamentation. 



He reminds us that Claus and Gerstaeker are of opinion that 

 Nebalia is not a Fhyllopod. Because Nehalia during its embryonal 

 life (whilst still in the egg) passes through the " Nauplius-" and 

 " Zoea-stages," which in Decapods occur partly in the free state, it 

 has been regarded, by some, as a " Phyllopodiform-Decapod ; " but 

 as it never attains a higher development as an adult than that of 

 a Phyllopod, and has no retrograde metamorphosis, may we not 

 with as equal reason regard Nebalia as a highly-organized Fhijllopod, 

 as to assert that it is a Decapod arrested at the Phyllopod stage ? ^ 



All who have studied the Phyllopoda have been struck by 

 the peculiar points of special interest to be observed in Nebalia.'^ 



Milne-Edwards, in his " Histoire Naturelle des Crustaces " (1840), 

 places Nebalia in the family Apusidce among the Phyllopods ; at the 

 same time he remarks, " The Nebalice are very singular little crusta- 

 ceans, which by reason of their stalked eyes,^ and their carapace, 

 approach the Podophthalmia ; they do not however possess branchiae, 

 properly so-called, but they respire by the aid of their thoracic feet, 

 which are developed into membranaceous and foliaceous appendages. 

 They resemble in many respects and establish a passage between 

 Mysis and Apus." 



Baird (1850) founded the family Nebaliada, and regarded Nebalia 

 as a Phyllopod. 



Prof. J. D. Dana (1853), in his great work on the Crustacea retained 

 the family name {Nebaliadce) , which he placed in the Phyllopoda. 



Metschnikoff, in 1865, published an abstract of his account of the 

 development of Nebalia Geoffroyi, and in 1868, the full essay in 

 Eussian. Fritz Midler, in his "Fiir Darwin," states that Metschnikoff 

 has observed, " that Nebalia, during its embryonal life, passes 

 through the Nauplius and Zoea-stages, which in the Decapoda 

 occur partly (in Penceus) in the free state." "Therefore," he adds, 

 " I regard Nebalia as a Phyllopodiform Decapod." 



In 1872, Claus gave an account, with excellent figures, of the 

 external anatomy of Nebalia Geoffroyi, and, in 1876, he described the 

 internal anatomy. 



In 1875, in the account of the Atlantic Crustacea of the 

 "Challenger Expedition," Willemoes-Suhm placed the Nebaliadce 

 among the ScJiizopoda. 



1 The potentiality/ of a form to attain to a higher existence seems to be mistaken 

 here for actuality. It is the story of the French soldier with the marshal's baton in 

 his knapsack and the American boy who feels within him the potentiality of becoming 

 some clay President ! 



2 For a very full and admirable account of Nebalia see the 12th Annual Report of 

 the United States Geological Surveys, Part I. Geology, Paleontology and Zoology, 

 8vo. 1883 (Washington), "A Monograph of the Phyllopod Crustacea of North 

 America, with remarks on the order PlujUocarida,'" by A. S. Packard, jun., pp. 

 295-592, and plates i.-xxxix. See also the "American Naturalist" for Oct. 

 Nov and Dec. 1882, vol. xvi. pp. 785, 861, 945. 



3 Pedunculated eyes are also present in Branchipus and Artemia, so that the 

 stalked eyes of Nebalia can hardly be regarded as an essential character. 



I 



