SOUTHERN CALIFORNIA ACADEMY OF SCIENCES 5 
thorax and the abdomen; the pincers of the scorpion are mod- 
ified into a pair of tactile palps; whilst the small mouth-pincers 
are elaborated into double-jointed fangs, having a poison-sac 
situated in the basal portion. The segmentation of the abdo- 
men disappears in most genera, and the organ becomes soft. 
The abdominal appendages disappear, with the exception of 
the 2 last pairs, which, m this order only, become spinning 
mamille. Some spiders, like scorpions, breathe by means of 
lung-saes, the higher forms by tracheal tubes. 
Fig. 6. In the Solifuge, or scorpion-spiders, the cephalo- 
thorax is divided into 3 somites; the abdomen approximates to 
the spider shape, and the telson is lost. The pincers become 
oripping-jaws, having their axes in a vertical instead of a hori- 
zontal plane. 
Distribution. We come next to the distribution of the 
Arachnida. The Spiders are cosmopolitan, to as far north as 
Greenland and Spitzbergen. 
The Seorpions are found in both hemispheres, between lines 
represented, roughly, by the 45th parallel of north latitude and 
the 47th parallel of south latitude. 
The Whip-tails are found in the south of North Ameriea, 
Central and South America, in India, China, and Polynesia. 
The Phrynichidxe occur in the same area of this continent as 
the preceding order, plus Patagonia; in Africa, India, China, 
and Polynesia. As might be expected from the topsy-turvy 
geology of Australasia, its scorpions differ greatly from those 
of the other regions, and are entirely absent from New Zealand. 
This absence, in view of the fact that they are found in all the 
other islands of the Polynesian archipelago, is one of the, as 
yet, unsolved problems of arachnology. Neither the whip-tails 
nor the Phrynichide are found in Australasia. 
In North America, the northern limit of scorpions seems to 
be between the 35th and 40th parallels, on a line approximately 
bisecting this state and Virginia on the Atlantic coast. To 
this region has been given, for the purposes of taxonomy, the 
name of the Sonoran province of Merriam. In California, 4 
genera have so far been established; namely—Uroctonus, Ha- 
drurus, Vejovis and Centrurus. The wnip-tails and Phry- 
nichidxw have been found as far north as Lower California; and 
I am hopeful they may be found in favorable, that is, desert 
and sandy loealities in Southern Californi. Of the Solifugz, 
Mr. Banks names 2 genera as found in California, one of which 
together with 2 genera of scorpions, I have found at Whittier. 
Physiology. We come now to the physiology of these Ara- 
ehnida. As with all other animals, their life-activities are di- 
rected to 3 main ends: nutrition or offense, defense, and re- 
