Mygalomorphe tn the British Museum. 229 
on the first or second legs are complete, those on the fourth or 
even the third may still retain their divisional line. 
This generalization with’ regard to the growth of the pads 
will perhaps be found to admit of some exceptions in detail ; 
but, on the whole, I believe it will prove to represent the facts 
of the case with tolerable accuracy. Hence it 1s worthy of 
remembrance in connexion with the determination of the 
genera and species of the group. For instance, Mons. Simon 
primarily divides his vast family Aviculariin as follows :— 
A. Scopule at least of the posterior tarsi 
divided. 
a, Scopulee of all the tarsi divided ...... Ischnocolee. 
b. Scopule only ofthe posterior tarsi divided. 
a. Scopulee of third and fourth tarsi 
Givad ed et 2 <i geina hackle dae shapers Chetopelmatee. 
b. Scopulee of the fourth tarsi divided .. Crypsidromee (and 
Phlogiee *). 
B. Scopule of all the tarsi undivided,...... Aviculariee, Theraphosee, 
Eurypelmatee, Home- 
ommatee (Selenocosmiee, 
Pecilotheriee +). 
But in accordance with what has been said regarding the 
growth of the scopule, it follows that a species of section B 
will in its early days fall into the Ischnocolez, a little later 
into the Chatopelmatez, then into the Crypsidromee. And, 
similarly, a species belonging to the Crypsidromez will have 
to pass through sections a and a before reaching its destina- 
tion in b. 
Hence it follows that the division of the scopule may be 
nothing but a sign of immaturity. I am_ particular to 
emphasize the verb in this sentence because [ do not wish to 
be misunderstood to say that the character belongs necessarily 
to undeveloped forms. ‘This is certainly not the case, since 
many adults are found with some or all of their tarsal pads 
divided. But I consider that one cannot too strongly insist 
upon the necessity for caution in the use of this character on 
the part of authors who are systematically studying the 
Mygalomorphe, seeing that both Ausserer and Keyserling, 
who are looked upon as high authorities in arachnology, have 
established a large number of spurious species, perhaps even 
genera, upon this very character, when occurring in specimens 
* The Phlogieze need not here be taken into consideration, since I 
have already endeavoured to show that they form part of a group to 
which I gave the family name Selenocosmiide, and have no particular 
relationship with the Crypsidromee (Ann. & Mag. Nat. Hist. (6) xv. 
pp. 165-169), 
t+ Already discussed, eid. 
