ATLANTIC AND CARIBBEAN PYCNOGONIDA—HEDGPETH 177 
Antarctic species, and Marcus’s (1940b) excellent catalog of the 
Brazilian and South American pycnogonids. Bronn’s Tierreich 
monograph by Helfer and Schlottke (1935) is the first general account 
of the class as a whole, but it is marred by minor errors in the bibliog- 
raphy and the haphazard treatment of several generic names. Of 
the older monographs, those by Dohrn (1881) on Mediterranean 
species and Sars (1891) on the Norwegian species are classics and 
indispensable references. Both are beautifully illustrated. 
The determined reader who ventures into the following pages in 
search of further enlightenment will do well if he survives with any 
vestige of the patience that has served him this far. Why are species 
in some genera separated by characters ignored in other genera, why 
this dwelling on the lengths of claws, or this petty quibbling over 
names themselves? He will soon suspect that ‘“‘species’ are sub- 
jective appraisals, that the conception of what constitutes a species 
varies with the one who specifies. In the words of the late Dr. Tate 
Regan, “‘A species is a community, or a number of related communi- 
ties, whose distinctive morphological characters are, in the opinion 
of a competent systematists, sufficiently definite to entitle it, or them, 
to a specific name.’’ As Julian Huxley observes, in commenting on 
this definition, the difficulty is in the word ‘‘competent.” ‘And 
experience,’ he continues, ‘‘teaches us that even competent systema- 
tists do not always agree as to the delimitation of species.’’™ 
This, of course, is another way of suggesting that a species is per- 
haps an anthropomorphic conception rather than a natural entity. 
As Darwin said, ‘‘No one definition has satisfied all naturalists, yet 
every naturalist knows vaguely what he means when he speaks of a 
species.”’ It does not seem, however, that a species is as artificial as it 
appears to be in taxonomic papers—the fault is not in our species but 
in ourselves—and I cannot agree with the famous remarks in the 
conclusion of the “Origin of Species’’: ‘‘We shall have to treat species 
in the same manner as those naturalists treat genera, who admit that 
genera are merely artificial combinations made for convenience. This 
may not be a cheering prospect; but we shall at least be freed from the 
vain search for the undiscovered and undiscoverable essence of the 
term species.” Darwin was an optimist; we are more deeply en- 
grossed in that vain search than ever, standing, in the words of Henry 
Adams, on the shore of a sunless sea, “diving for pearls and never 
finding them.” 
That the taxonomist is a practitioner of a branch of metaphysics 
has been suspected by some writers, although few have explicitly 
ul Julian Huxley, ‘Evolution: The Modern Synthesis,”’ p. 157, 1943. 
12 Leon J. Cole, who began as a pycnogonid student and is now a geneticist, has presented an interesting 
discussion of these matters in his article ‘‘Each after his Own Kind,” Science, vol. 93, pp. 289-293, 316-319, 1941. 
