482 Mr. Blackwall on undescribed Species of Araneide. 
developed, not very complex in structure, and are of a brown colour 
tinged with red. Eyes distributed in pairs on the anterior eminence of 
the cephalothorax; one pair is situated on the summit of its superior seg- 
ment, another on a small prominence on the upper part of the inferior 
segment, in front ; these eyes describe a narrow trapezoid whose shortest 
side is before; the third and fourth pairs are seated on the sides of the 
frontal eminence, and are geminated. Each tarsus is terminated by three, 
claws ; the two upper ones are pectinated, and the lower one is inflected 
near its base. Abdomen oval, convex above, projecting over the base of 
the cephalothorax ; it is thinly covered with hair, glossy, and of a brownish 
black colour. The plates of the spiracles are pale yellow. 
Length, from the anterior part of the cephalothorax to the extremity of 
the abdomen, ,th of an inch; length of the cephalothorax ,; breadth 
s+; breadth of the abdomen ;*,; length of an anterior leg +4; length of 
a leg of the third pair +4. 
I found this spider in March 1835, at Oakland, under stones; but ob- 
tained specimens of males only. ‘ 
Walckenaéria depressa. 
Cephalothorax of a short oval form, convex, prominent, but obtuse, 
before, where the eyes are situated, depressed in the posterior region, 
without any indentation in the medial line. Mandibles moderately strong, - 
concave, and slightly inclined towards the pectus, which is broad and 
heart-shaped. The anterior and posterior pairs of legs, which are the 
longest, are equal in length, and the third pair is the shortest. These 
parts, with the maxille and lip, are of a deep brown colour, the cephalo- 
thorax, pectus, and lip being much the darkest. Each tarsus is terminated 
by three claws; the two superior ones are curved and pectinated, and the 
inferior one is inflected near its base. The third and fourth joints of the 
palpi are short; the latter is the larger, and has two strong apophyses in 
front, the outer one of which is the more prominent: the fifth joint is oval, 
convex and hairy externally, ccricave within, comprising the palpal organs ; 
they are highly developed, complicated in structure, with a curved, spiny 
process at the extremity, and are of a deep red-brown colour. Abdomen 
oval, somewhat depressed, pointed at the spinners, and projects over the 
base of the cephalothorax; it is thinly covered with hair, glossy, and 
brownish black. Plates of the spiracles deep brown. Aged individuals 
have the legs of a dark red-brown colour. 
Length, from the anterior part of the cephalothorax to the extremity of 
the abdomen, +;th of an inch; length of the cephalothorax ,; breadth 
sz; breadth of the abdomen ~,; length of an anterior leg +-; length 
of a leg of the third pair +4. 
The specimens from which the description was made were taken under 
stones, in a wood at Oakland, in April 1835. Males alone were cap- 
tured. 
Walckenaéria obtusa. 
There is a striking resemblance between the male of this species and the 
male of Walckenaéria cuspidata* ; the following are the principal points of 
difference. The male of Walckenaéria obtusa is decidedly the larger, its 
pectus is more elongated, it has a slight indentation in the medial line 
of the posterior region of the cephalothorax, and has no acute, conical 
prominence situated within the trapezoid formed by the four intermediate 
* For the description of Walckenaéria cuspidata, see Lond. and Edinb. 
Phil. Mag., vol. iii. p. 108, 
