OF THE AMERICAN KING-CRAB. © 501 
their nerve-pairs and probably ganglion-centres within, but soldered together or ** anchy- 
losed,” in Kónig's and Baily's Belinurus. 
Should any persevere in objecting to the King-crabs’ being called Crustacea with 
others the objection may be stronger to call them Arachnida or Myriapoda. Cha- 
racters common to Limulus, with allied extinct gill-bearing, well-limbed Articulata, 
have not a class-value. I believe myself at one with the best Carcinologists in refusing 
to raise the Merostomata to an equivalency with Crustacea, i. e., to run them parallel 
with and alongside of the rest of the branchiated Condylopods. A class, after all, is an 
artificial group, a help to the classifier. One may call Limulus a Crustacean, and yet 
discern in its anatomy the evidence of its more generalized structure as compared with 
the Malacostraca. The merostomatous type preceded that of either the macrourous or 
brachyurous Crustacea ; and in Limulus, the sole living representative, we have been able 
to detect characters subsequently over-riding the crustaceous one, and intensified in the 
air-breathing members of the Apterous Insecta of Linnzeus. 
As compared with its longer-bodied and many-segmented predecessors, Limulus itself 
shows a concentrative specialization; but vegetative repetition still reigns in the limb- 
series. “Internal antenules,’ ‘external antenne,’ ‘mandibles,’ * maxille,’ * maxillipeds,’ 
‘legs,’—all work together by their spinigerous haunch-joints in subserviency to mastica- 
tion, and all terminate in chelæ. As compared with modern crabs, no structure is more 
striking and significant than the resistence, so to speak, of the heart in Limulus to the 
concentrative tendencies; it is still the dorsal vessel, though the body-part containing it 
has the breadth and shortness of the carapace of the crab, in which the heart is shaped 
to match. In both Merostome and Brachyure the neural axis supplying the cephal- 
etral limbs is annular: but, in modern crabs, the subcesophageal part is defined by 
distance and by concomitantly elongated and slender, ‘crura, or connecting tracts be- 
tween it and the supracesophageal or cerebral part. This differentiation had not taken 
place in Belinurus, Neolimulus, Prestwichia, and other palzozoie predecessors of Bra- 
chyura, whose organization we have to thank their longer-lived, lingering representative 
genus for enabling us to peer into. 
That such glimpses, with concomitant tracing of the development of the individual 
Limulus, afford us some ground, and that the like work, with continued and persevering 
quest of its palseozoic fossil allies, may afford more ground for at least guessing at the 
ways in which a preordained plan of derivation by congenital departures from parental 
form have operated in originating the various branches from a common ancestral arti- 
culate stem, is an encouraging faith. 
That old Ocean should have afforded the chance conditions of origin of crustaceous 
subelasses, orders, genera, species, by * Natural Selection,” is not conceivable by me: the 
metaphysical fact that there is * will,’ that a * sense of the beautiful’ exists, that ‘a love 
of virtue' operates, opposes the supposition. Such fact sufficeth for the rejection of a 
* Nature' working without will, taking no counsel of either the good or the beautiful, 
casting up from her dark abyss only eternal transformations of herself, furthering, with 
the same restless activity, decline and increase of organs, death and life of indivi- 
duals, extinction and origination of species. Nevertheless I hold by the conviction that 
