68 
W. F. PURCELL. 
themselves constitute the eutapophysis, which is, of course, 
formed by the entire ectodermal invagination — that is to say, 
in this case the medial tracheal trunks. 
The tracheae in the Dysderidse. — These tracheae, which have 
been frequently described,^ were the first found in spiders 
(by Leon Dnfour® in 1834, teste Bertkau, ’72, and Lamy, 
:02), and ai’e of considerable interest from a comparative ana- 
tomical point of view. I have myself examined sections of 
Segestria, Harpactes, and Dysdera. 
The tracheal spiracles of the Dysderidm are widely 
separated, lying in the anterior region of the body a little 
behind the pair of pulmonary spiracles (text-fig. 3, p. 69), 
and entirely unconnected with one another. Each leads into 
a large tracheal trunk, which rises upwards from the spiracle 
and then runs forwards and bi'eaks up at its anterior end, 
either in the pedicel of the abdomen or a little behind it, into 
a larg-e bunch of fine secondaiy tubules. At the base a 
shorter posterior trunk projects backwards, and also gives 
off a number of fine tubules. The chitinous lining of the 
trunks is provided Avith spines, which support a spiral thread 
(Dysdera) or an inner perforated tube (Segestria).^ To 
these well-known facts I have to add the following observa- 
tions : 
The segments of the venti’al longitudinal muscles belonging 
to the tracheal somite are very short in this family, like the 
somite itself, and the entosternite is attached on the medial 
' Literature : Duges ['36, '49 ; v. Siebold ('48. p. 535) also cites the 
following of the year 1835 : ‘ Feuill. Acad, des Sci. Seance du 9. 
Fevr.,’ also Froriep's ‘ Notizen,' xliii, p. 231. also ‘ Ann. Sc. Nat.,’ at, p. 
183], BertkaAi {'72), MacLeod ('80). Lamy (:02). 
- 1 am unalde to find the reference to this pajAei-, unless it he ‘ le 
Temps,’ No. 1942, cited l>y Menge ('51. jj. 22), Avhich, howcA-er, v. Siebold 
('48. p. 5.35) accredits to A. Duges, both authors giving tlie year 1835, 
and not 1834. 
Bertkau (’72) states that in Segestria these spines do not anas- 
tomose, but Lamy (:02, j). 183, fig. 23) has since shoAvn (and 1 can 
coi’roborate his statements) that they certainly anastomose at their 
ends, forming an inner, fenestrated, chitinous tul)C. In Harpactes 
the anastomosing branches of the spines form a sinq)le network only. 
