370 Mv. J. Blackwall on newly discovered Spiders me to the same eflFect, he having seen this fossil. The animal, of which the head is wanting, is abundantly endowed with feathers. It possesses a long tail, like Khamphorhynclms, and a small pelvis ; like birds, it has a single bone forming the tarsus; it is furnished with three toes ; on the anterior limbs there is a fan of feathers, and also on the tail, on which the feathers radiate, not from the last vertebra, but laterally along the vertebrae. The simple tarsus of itself shows that this animal does not belong to the Pterodactyles, and the formation of the tail contradicts the idea that we connect with our birds, yet the feathers are not distinguishable from those of birds. The fossil feather from Solenhofen described by me wdll be derived from a similar ani-mal, for which I have selected the name of Archaopteryx litho-graphica^. XLI. — Descriptions of newly discovered Spiders from the Island of Madeira. By John Blackwall, F.L.S. A COLLECTION of Spiders recently made in the Island of Ma-deira, and presented to me by the Rev. Hamlet Clark, comprised the following species, which appear to be new or imperfectly known to arachnologists. Tribe Octonoculina. Family Thomisid^. Genus Thomisus, Walck. T/wmisus spinifer. Length of the male ^i\\ of an inch ; length of the cephalo-thorax y^ ; breadth y ^ ; breadth of the abdomen -^-^ ; length of an anterior leg ^ ; length of a leg of the third pair /q. The cephalothorax is broad, convex, glossy, slightly compressed before, rounded in front and on the sides, abruptly depressed at the base, provided with a few strong black bristles, those on the frontal margin being directed forwards, and is of a reddish-yel-low colour, an obscure band in the middle, which tapers from the eyes to its posterior extremity, being the palest. The eyes, which are seated on whitish spots, are disposed on the anterior part of the cephalothorax in two transverse curved rows, forming a crescent whose convexity is directed forwards ; the eyes of each lateral pair are placed on tubercles, those of the anterior row being the largest of the eight. The falces are short, cuneiform, and vertical ; the maxillae are obliquely truncated at the extre-mity on the outer side, and inclined towards the lip, which is triangular; the sternum is heart-shaped; the legs are very un-* Jahi-b. fur Mineral. 1861, p. 679.