ll 7 
; ON THE FOSSIL PHYLLOPODA OF THE PALOZOIC ROCKS. 333. 
2. The movable rostrum, loosely attached to the carapace. 
3. The very long and large mandibular palpus; the long slender 
appendage of the first maxilla, and the very long bi-ramous maxille. 
4, The absence of any maxillipeds. 
5. The eight pairs of pseudo-phyllopod thoracic feet, not adapted for 
walking. 
[To these we would add—Sa. The “telson”’ long and slender, with 
two long narrow setigerous cercopods as in the Copepoda. | 
6. The animal swimming on its back. 
7. No zoéa-formed larva. 
The characters which separate it from the Phyllopods are— 
1, Carapace not hinged; a rostrum present. 
2. Two pairs of well-developed long and large multiarticulate antenne ; 
the hinder pair, in the male, longer than the first pair. 
3. The thorax and its appendages clearly differentiated from the 
abdomen.’ ! 
Nebalia has been so long regarded as the surviving representative of 
those more ancient and gigantic forms of PHyLLocaripa, which existed in 
such numbers in the Cambrian and Silurian Seas, and became nearly 
extinct towards the close of the Carboniferous epoch, that any decision 
affecting its zoological position cannot be a matter of indifference to the 
paleontologist. 
But after studying its larval development and adult structural modifi- 
cations, we arrive at the fact that Nebalia is a more generalised type than 
is ordinarily to be found at the present day, ‘ combining Copepod, Phyllo- 
pod, and Decapod-like features, with other more fundamental characters 
of its own’ (Packard), which preclude us from regarding it as a true 
Malacostracan, and, although ancestrally related to that order, it never- 
theless does not attain, in our opinion, to the Malacostracan grade of 
development. They should therefore be arranged in a distinct order 
(the Puytuocaripa) between the Eyromosrraca and the MALAcosTRAca, as 
suggested by Claus. But if it is undesirable to have such an outstanding 
group, then we contend that the balance turns in favour of retaining it in 
the former division, if not in the order PHytiopopa as heretofore. 
Thus we conclude :— 
1. Some of the supposed ‘ Phyllopod shields’ from Budesheim and 
Bicken are probably Aptychi of Goniatites. 
2. That for others of the Palzozoic Phyllopods, described in the 
Reports of 1883-84, this explanation is inadmissible. 
3. That those which cannot be referred to Apftychi are still, in all pro- 
bability, Phyllopods. 
4, That the Nebalia-like forms, now placed in the order PHyuuo- 
CARIDA, are certainly not Decapods. And even if they may not with 
propriety be retained any longer in the old order Puy3iopopa (of which 
we are by no means sure), yet they may more correctly be placed beside 
» American Naturalist, 1882, vol. xvi. p. 951; and Monograph N. Amer. Phyllo- 
pods, &c, 1883, pp. 447-8. 
2 Dr. Packard writes, ‘ There is little to indicate that the Schizopods (ysis, &c.) 
have descended from a Webalia-like form, but rather from some accelerated zoéa 
form ; while the Phyllocarida have had no Decapod-blood in them, so to say, but have 
descended by a separate line from Copepod-like ancestors, and culminated, and even 
began to disappear, before any Malacostraca, at least in any numbers, appeared.” 
American Naturalist, 1882, vol. xvi. p. 873. 
