372 THE ORIGIN OF VERTEBRATES 
evidence as to their function is entirely wanting. With respect to the 
pectens of the scorpion (Fig. 151), it has been suggested that they 
are of the nature of copulatory organs, a suggestion which may be 
dismissed without hesitation, for they are not constructed after the 
fashion of claspers, but are simply elaborate sense-organs, and, as 
such, are found equally in male or female. 
The only observer who has hitherto 
specially studied the structure of the 
sense-organs in the pecten is, as far as 
I know, Gaubert, and he describes their 
structure together with that of the sense- 
organs of the racquets of Galeodes, in 
connection with the lyriform organs of 
arachnids, as though he recognized a 
family resemblance between the three 
sets of organs. 
The pecten of the scorpions is an 
elaborate sense-organ, or rather group of 
sense-organs, the special organ being 
developed on each tooth of the comb; 
its surface, which is frequently flattened, 
being directed backwards and inwards, 
when the axis of the pecten is horizontal 
at right angles to the length of the body. 
Fig. 151.—UnpbER SURFACE OF 7 F 
SCORPION (ANDROCTONUS). The surface view of this part of the tooth 
The operculum is marked out resembles that of the branchial organs or 
with dots, and on each side of the flabellum in Limulus, in that it 
a Se RSE ORE TING BY i thickly covered with circular patches, 
in the centre of which an ill-defined 
appearance as of a fine pore is seen, In Fig. 152, B, I give a sketch 
of the surface view of a part of the organ. 
Transverse sections of a tooth of the comb of Scorpio Huropeus 
present the appearance given in Fig. 152, A, and show that each 
of these circular patches is the surface-view of a goblet-shaped 
chitinous organ, Fig. 152, C, from the centre of which a short, some- 
what cylindrical chitinous spike projects. Within this spike, and 
running through the goblet into the subjacent tissue, is a fine 
tubule. The series of goblets gives rise to the appearance of the 
circular plaques on the surface-view, while the spike with its tubule 
