496 PROF. OWEN ON THE ANATOMY 
The varied and usually more or less dislocated positions of the jointed limbs in the 
fossil Merostomatous crustaceans would lead one to expect a like condition in other 
families of palseozoic fossils possessing similar appendages *. 
The difficulty of getting a clear view of the nature and affinities of Zimulus at the stage 
of anatomical investigation which had been reached before the date of the present paper, 
and the need of such further help as could be given by one occupying himself therewith 
by the way, as it were, and in the brief snatches of leisure which administrative duties 
and the cultivation of more congenial fields of original research might permit, will be 
appreciated from the fact that one who has devoted to this question so much pains, and 
skill, and dialectic ability as the indefatigable crustaceologist Dr. Anton Dohrn has left 
his conclusions as to the class-characters e. y. of Limulus in a condition, to say the 
least, not so supported as to command the common consent of his fellow labourers. 
For myself it is a plain duty, and under responsibility for opportunities of dissection so 
kindly and liberally afforded by American friends, to give my reasons for dissenting from 
the view of Limulus being so far Arachnidan as to require, with its extinct allies, to 
be placed as a distinct group, not of, but by the side of, the Crustacea t. 
In these questions the nervous system yields important indications. If it were a fact 
that “in Limulus only the foremost pair of limbs was innervated from the superceso- 
phageal ganglion, the rest deriving their nerves from the abdominal ganglionic 
chain ”ł, the advocate for its elimination from the Crustaceous class would have an 
argument of weight for the affinity of Limulus and its extinct allies with the Scorpion 
and Spider. 
The allies here referred to are those possessing cephaletral limbs the general characters 
of which are repeated in Limulus. 
* The above considerations incline me to view, as the more probable interpretation of the appearances in this fossil, 
that given by the accomplished naturalist Dana, to whose writings, and especially those on the Crustaceous class, 
I am indebted for much interesting and valuable knowledge. 
+ “ Limulus ist zunächst verwandt mit den Gigantostraken ; beide erscheinen verwandt mit den Trilobiten, obwohl 
diese Verwandtschaft nicht in alle Details nachgewiesen werden kann. Die morphologisch-genealogischen Bezie- 
hungen dieser drei Familien zu den Crustaceen lassen sich vor der Hand nicht feststellen, bleiben vielleicht für immer 
zweifelhaft.—Sonach bleibt uns nur übrig, diese drei Familien unter einem gemeinsamen Namen, wofür ich Hickel’- 
schen Ausdruck ** Gigantostraka? möchte in Vorschlag gebracht haben, selbständig zu constituiren und im System 
neben die Crustaceen zu stellen." . . . * Was bei Savigny andeutungsweise, bei Strauss-Dürckheim mit Einseitigkeit 
ausgesprochen wurde, das tritt also jetzt unter dem Gesichtspunkte der Descendenzthéorie von Neuem auf. Die 
Verbindung der Arachniden mit den Crustaceen soll durch Limulus und die ihm verwandten Eurypteriden gegeben 
sein.”—P. 638. [What Savigny has indicated and Strauss-Dürckheim has partially (one-sidedly) expressed, re- 
appears now under the light of the theory of evolution (descent)—that the connexion of Arachnids with Crustaceans is 
given by Limulus and the allied Eurypteride. Limulus is most nearly allied to the Gigantostraca ; both appear to be 
allied to the Trilobites, although this affinity cannot be shown in all details, The morphologico-genealogical relations 
of these three families to the Crustacea cannot be stated at present, and will remain, perhaps, always dubious. At 
present we are entirely unable to say any thing of their relations to the Arachnida. Consequently only one course 
remains for us, viz. to form an independent group for these three families, with a common name, adopting that of 
Gigantostraka proposed by Hæckel, and to place it in the system at the side of the Crustacea. ] 
i * Bei allen Krustern empfangen nämlich die beiden vorderen Extremitütenpaare ihre Nerven aus dem oberen 
Schlundganglion. Bei Limulus aber wird nur das vorderste,Paar der Gliedmaassen von dem oberen Schlund- 
ganglion versorgt, die übrigen empfangen ihre Nerven aus der Bauchganglionkette."— A. Domes, loc. cit. p. 585. 
