8 PYCNOGONIDA. 
next introduced the expression pollex (i. e. thumb) for this process, though this latter name had already 
been used by O. Fabricius and Krøyer of the last joint of the cheliforus, the movable finger. 
Movable finger (p0//ex v. digitus mobilis), fig. 1 dm. 
O. Fabricius: pollex; Krøyer: Tommel (pollex); Hoek: griffe mobile des mandibules; 
Wilson: dactylus; Bøhm: Scheerenfinger or Daumen; Hansen: Index; Sars: bevægelige Finger 
(dactylus). 
I have kept the old name of O. Fabricius and Krøyer pollex or movable finger for the 
terminal joint of the cheliforus, or the movable finger of the hand, and can see n0 reason to intro- 
duce instead of it the dactylus of Wilson. 
To avoid every misconception it would perhaps be best to omit the use of the short names of 
pollex, dactylus, index, and thumb, and to abide by the appellations digitus immobilis and digitus 
mobilis, immovable and movable finger, as I have done in the synoptical figure by choosing the 
letters døm and dm. 
Ambulatory leg (pes ambulatortus), fig. 1 pa ander 
Schimkéwitsch, Pantop. «Vettor Pisani», gives to the first pair of ambulatory legs also the 
separate name: Patte-måchoire. ; 
"The rise and development of the four pairs of ambulatory legs follow the larval development, 
and they are never wanting im the imago, nor reduced in any way but at most by the defective devel- 
opment or the falling off of the claws or the auxiliary claws. They arise from the ends of the lateral 
processes of the body, and are, to judge from the rudiments im the embryo and the larva, as has been 
mentioned, only prolongations of these processes, constricted into the number of nine joints, inclusive 
of the claw, which is common to all Pycnogonida. 
First coxal joint (arzrculus coxalis primus), fig.1 €. 
Second coxal joint (ertieulus coxalis secundus), fig.1 2. 
Third coxal joint (articulus coxalis tertrus), fig. 1 6. 
Sars: 3 Hofteled (articuli coxales). 
These three joints form the proximal end of the ambulatory leg; they belong to the shortest 
joints of the leg, and form a series of homonomous joints, being of one set; therefore they may all 
together correctly be termed the coxa. 
Femoral joint (/em%u7), im 72 
Sars: Laarled (articulus femoralis). 
In the Arthropoda, especially the Insects, the femoral joint follows upon the coxa and coxal 
segment or trochanter, which in these animals is only a subordinate joint. I think it, however, im- 
possible to transfer the terminology of the legs of the Insects to those of the Pycnogonida, and there- 
fore I have considered it advisable to follow Sars in his appellations of the joints of the leg, only 
with some variation in the special names. 
First tibial joint (artzeulus trbralis prior), fig. 1 6. 
Second tibial joint (arzzculus tibralis alter), fig. 1 zb2. 
Sars: Lægled (articuli tibiales). 
"These two joints of the leg are closely united, and there is 10 reason to give any prominence 
