STRUCTURE AND ECONOMY OF SPIDERS. 323 
on the present occasion to name the Mygale ursina 
of Koch, the Mygale zebra of Walckenaer, and the 
Atypus Sulzeri of Latreille. 
Near the extremity of the outer margin of the 
maxillz of numerous species of spiders there is a 
- slight dark-coloured ridge, surmounted by a series of 
extremely minute close-set spines, which I have long 
known and regarded as contributing to give firmness 
to the most exposed part of those organs, and as 
affording some assistance in restraining the action 
and in the retention of the insects on which such 
spiders prey. Miss Staveley, on examining this struc- 
ture under a high degree of magnifying-power, has 
arrived at the conclusion that it may be resolved into 
a row of minute teeth (Ann. & Mag. Nat. Hist. ser. 3. 
vol. xvii. p. 399)—an opinion which its connexion 
with the maxille would probably tend to suggest ; 
by its position and conformation, however, it appears 
to be little, if at all, adapted to aid in the office of 
mastication. 
As the maxille of those species of the family 
Mygalide that have the palpi articulated at or near 
their extremity might be expected to present other 
modifications of structure, it became an object of some 
interest to subject them to a careful examination ; 
with this view, I dissected several specimens of the 
Mygalide, belonging to different genera, from which I 
obtained the following results :—In no instance was 
any appearance of a ridge provided with a series of 
Te 
