526 PYCNOGONIDA te acrim 
this unimportant numerical coincidence ; nor is there any signifi- 
cance in the apparent outward resemblance to isolated forms (e.g. 
Cyamus) that induced some of the older writers, from Fabricius 
downwards and including Kroyer and the elder Milne-Edwards, 
to connect the Pycnogons with the Crustacea. To refer them, 
or to approximate them to the Arachnids, has been a stronger 
and a more lasting tendency.’ Linnaeus (1767) included the 
two species of which he was cognisant in the genus Phalangium, 
together with P. opilio. Lamarck, who first formulated the 
group Arachnida (1802), let it embrace the Pycnogons; and 
Latreille (1804, 1810), who immediately followed him, defined 
more clearly the Pycnogonida as a subdivision of the greater 
eroup, side by side with the subdivision that corresponds to our 
modern Arachnida (“ Arachnides aceres”), and together with a 
medley of lower Crustacea, Myriapoda, Thysanura, and Parasitic 
Insects; he was so cautious as to add “j’observerai seulement, 
que je ne connais pas encore bien la place naturelle des Pyeno- 
gonides et des Parasites,” and Cuvier, setting them in a similar 
position, adds a similar qualification.” 
Leach (1814), whose great service it was to dissociate the 
Edriophthalmata and the Myriapoda from the Latreillian medley, 
left the group Arachnida as we still have it (save for the inclusion 
of the Dipterous Insect Nycteribia), and divided the group (with 
the same exception) into four Orders of which the Podosomata, 2.e. 
the Pycnogonida, are one. Savigny (1816), less philosophical in 
this case than was his wont, assumed the Crustacean type to pass 
to the Arachnidan by a loss of several anterior pairs of appen- 
dages, and appears to set the Pycnogons in an intermediate grade, 
marking the pathway of the change. He considered the seven 
pairs of limbs of the Pycnogons to represent thoracic limbs of a 
Malacostracan, and, like so many of his contemporaries, was much 
biased by the apparent resemblance of Cyamus to Pycnogonum. 
The reader may find in Dohrn’s Monograph a guide to many 
other opinions and judgments, some of them of no small morpho- 
logical interest and historical value*; but it behoves us to pass 
1 Cf. Carpenter, Proc. &. Irish Acad. xxiv., 1903, p. 820; Lankester, Quart. 
J. Mier, Sei. xlviii., 1904, p. 223; Bouvier, Hap. Antarct. Fr., ‘“‘ Pycnogonides,” 
19075 7p. /, ete: 
2 “Nous ne les placons ici qu’avec doute,” Regne Anim. éd. 3, tom. vi. 
p. 298. 
3 Of, also J. E. W. Ihle, ‘‘Phylogenie und systematische Stellung der Panto- 
