62 
W. F. PUKCELL. 
figured by Simmons do not resemble pulmonary folds; being 
on the opposite sides of the tracheal tube, and they can 
hardly be “ tracheal twigs ” as Simmons suggests, since the 
lateral trachea? are, I believe, unbranched in the two forms 
examined. 
The Attus-type and similar types of tracheae in other spiders. — 
The Attus-type of tracheae has been found in various other 
genera of Attidm (Bertkau, Lamy), and is possibly the pre- 
vailing type in this family. 
A very similar type, not sharply separable from the 
Attus-type, has been described by Bertkau and Lamy under 
the name arborescent type of tracheae, on account of 
the moi’e frequent branching of the twigs given off by the 
imiin trunks. Other differences, according to Lamy, are 
the presence of a spiral thread in the main trunks, and the 
prolongation of these trunks into the cephalothorax. Such 
trachea? have been found in the Uloboridse (Uloborus, 
Lamy, :02, fig. 3, Miagram mopes, fig. 5), Prodidomidae 
(fig. 26), Zodariidae (Zodarion, fig. 31), Clubionidae 
(Anyphaeua, fig. 51) and Attidae (Ballus, fig. 67).^ 
In all these forms the main trunks probably represent the 
entapophyses, while the small, branched, lateral lobe at the 
base of each trunk is, no doubt, the i-udimentary homologon 
of a pulmonary sac, exactly as in Attus floricola. 
Lamy failed to recognise the homologon of the pulmonary 
sacs in these lateral lobes in the arborescent and Attus- 
types of trachea?, and supposed that here the ectodermal 
tendons and the lateral trunks (representing the pulmonary 
sacs) were completely fused together and no longer distin- 
guishable. He also strangely misunderstood my statement 
on the subject, for he quotes (:02, pp. 257 and 260) me as 
having said that in the Attida? the homologon of the pul- 
monary sac takes no part in the formation of the trachem, 
which are entirely formed of the entapophyses, and he then 
proceeds to dissent from this view.- My actual statement 
' The figirres referred to are all in Lamy (:02). 
■i Thus on p. 2fi0 he says: “ En tout cas, I'opinion de Purcell sur les 
