386 ARACHNIDA—ARANEAE CHAP. 
a natural group, some of the families having apparently much 
closer affinities with certain of the Ecribellatae than with one 
another. This is especially evident in the case of the cribellate 
Oecobiidae and the ecribellate Urocteidae (see p. 392), which 
most authors unite in a single family. 
After all, the larger divisions of the order are not of great 
importance, and in the present chapter Simon’s linear arrange- 
ment of families will in the main be followed, except for the dis- 
tribution of the eight families which constitute his Cribellatae ' 
to the positions which a more general view of their structure 
would seem to indicate. 
Fam. 1. Liphistiidae.—Spiders with segmented abdomen, as 
shown by the presence of a series of tergal plates. Hight spin- 
nerets in the middle of the ventral surface of the abdomen, far 
removed from the anal tubercle. Sternum long and narrow. 
Hight compact eyes on a small eminence. Four pulmonary stigmata. 
This Family includes a single genus and two species of large 
spiders (about two inches in length), one from Penang and one 
from Sumatra. Very few examples have been found, and these 
are more or less defective and in bad condition. In some respects, 
especially the distinct segmentation of the abdomen, this genus 
much more nearly approaches the Pedipalpi than do any others 
of the order. No other spider possesses more than six spinning 
mamumillae, but it is possible that eight was the more primitive 
number, and that the “cribellum” (see p. 526) of the so-called 
Cribellate spiders is derived from 
the pair now possessed by Liphistius 
alone. 
Some Arachnologists consider the 
genus Liphistius so different from 
Fic. 201.—Profile (nat. size) and all other spiders as to constitute in 
eae ea (enlarged) of Liphistius itself a sub-order, for which, on 
account of the position of its spin- 
nerets, the name MESOTHELAE has been suggested, all other 
forms falling into the sub-order OPISTHOTHELAE. 
Fam. 2. Aviculariidae. (Mygalidae).’—Spiders with inde- 
 Simon’s Cribellatae comprise Hypochilidae, Uloboridae, Psechridae, Zoropsidae, 
Dictynidae, Oecobiidae, Eresidae, Filistatidae. 
2 The Spider genus Mygale was established by Walckenaer in 1802, but the 
name was preoccupied, having been used by Cuvier (Mammalia) in 1800. 
