1 882.] The Paleozoic Allies of Nebalia. 947 



eyes being still beneath the carapace." It is evident from this 

 that Mr. Salter regarded the fossil genera he enumerates as allied 

 to and as the ancestors of Nebalia, and as representatives of it in 

 Palaeozoic times. He evidently adopted the views of Milne- 

 Edwards and others as to the Phyllopodous nature of Nebalia. 



Discarding the Phyllopod forms, we here reproduce Salter's 

 figures and geological succession, which has been confirmed by 

 the discoveries of Barrande and H. Woodward. Salter's figure 

 of Nebalia is, however, replaced by an original one of Nebalia 

 bipes. 



In his article on the structure and systematic position of Ne- 

 balia, 1 Claus thus refers to the Palaeozoic forms : 



" It is generally considered that the oldest Palaeozoic Crusta- 

 cean remains whose shells and form of the body partly resemble 

 Apus and partly show a great similarity to Nebalia, for this rea- 

 son are considered to be Phyllopods, though we are without any 

 information as to the nature of the limbs. But now the instruc- 

 tive error, to which the consideration of Nebalia gave occasion, 

 will lead us to exercise greater caution in the interpretation of 

 such incomplete and imperfectly known remains. 



" In Ceratiocaris Salter, we have a great Nebalia-like carapace 

 by which a series of free segments were covered, and moreover a 

 long well-separated, lancet-formed rostrum. On the other hand, 

 the form of the abdomen, with the powerfully developed telson 

 beset with lateral spines, indicates a different form, which also 

 finds expression in the appendages of C. papilio Salt., figured as 

 antennae or thoracic limbs. If these representations indicate true 

 limbs, then they remind us most of the larval limbs of Decapods. 

 So also the position of Dictyocaris Salt., and Dithyrocaris of 

 Scouler to the other Silurian fossils regarded as Phyllopods 

 (Hymenocaris, Peltocaris) will remain problematical until we have 

 obtained more precise explanations as to the nature of their 

 limbs. 



" It is in the highest degree probable, however, that all these 

 forms are not true Phyllopods, but have belonged to a type of 

 Crustacea of which now there are no living representatives, but 

 which, taking their origin from forms allied to the lower types of 

 Entomostraca, have prepared the way for the Malacostracan type. 

 Such a connecting link, which has served to the present day, we 

 evidently find in the genus Nebalia." 



In 1879, 2 without knowing the views of Claus, just quoted, we 



1 Siebold u. Kolliker's Zeitschrift, xxn, 1872, p. 329. 

 ican Naturalist, February, 1879, Vol. xill, p. 128. 



