666 Mr. BrzackwaLus Descriptions of new Species of Spiders. 
loped, and very complicated in structure, having on the outer side of the 
upper part a curved, corneous process, bifurcated at the extremity, an 
obtuse, glossy prominence lower down, and a long, acute spine directed 
downwards and outwards ; they are of a dark red-brown colour. Abdo- 
men oviform, convex above, projecting over the base of the cephale- 
thorax; it is thinly clad with hairs, glossy, and brownish black. Plates 
of the spiracles dark brown. : à 
Adult males of this species were taken in June 1836, on rails at Oakland. 
49. Linyphia gracilis. Mas nigricans ; mandibulis maxillis pedibus palpisque 
brunneis paululùm rufo tinctis. 
Length of the male pzth of an inch; length of cephalo-thorax ; breadth 
3a; breadth of abdomen 30; length of an anterior leg +; length of a leg 
of the third pair yọ- ; 
Anterior part of the cephalo-thorax compressed; sides marked with furrows 
diverging from the upper part to the margins; in the medial line of the 
posterior region there is a large indentation. Mandibles conical, armed 
with a few teeth on the inner surface, and inclined towards the sternum, 
which is heart-shaped, convex, glossy, and provided with some scattered 
hairs. Maxille strong, enlarged at the base, where the palpi are inserted, 
and slightly inclined towards the lip, which is semicircular and prominent 
at the extremity. The cephalo-thorax, sternum, and lip are brownish 
black, and the mandibles and maxillz brown, faintly tinged with red. 
The posterior eyes of the trapezoid are the largest, and the anterior ones 
much the smallest of the eight. Legs long, slender, and pale brown, 
tinged with red. The palpi are short, and resemble the legs in colour, 
with the exception of the terminal joint, which is darker; fourth joint 
much stronger than the third; fifth oval, convex and hairy externally, 
concave within, comprising the palpal organs, which are prominent, 
highly developed, complicated in structure, with a small, glossy protu- 
berance on the outer side of the upper part, and a fine spine at the ex- 
tremity, enveloped in a delicate membrane, and curved into a circular 
form; they are of a red-brown colour. The convex sides of the terminal 
joints are directed towards each other. Abdomen oviform, convex above, 
