382, Mr. J. Blackwall on new Spiders from. Madeira. 
in the middle, and near the anterior extremity there is a minute 
circular depression on each side of the medial line; the under 
part is rather the palest, and has a branchial and tracheal stigma 
on each side of its anterior extremity. 
Family Gcopirpz. 
Genus (Ecosius, Lucas. 
CEcobius navus. 
Ccobius navus, Blackw. Aun. & Mag. Nat. Hist. ser. 3. vol. iv. p. 266.8 
Several specimens of Cicobius navus were comprised in the 
collection of Madeiran Spiders presented to me by the Rev. 
Hamlet Clark, and among them an adult female, a careful ex- 
amination of which has led to the establishment of important 
characters either previously unrecorded or regarded as doubtful. 
The dimensions of this species, as given in the ‘ Annals and 
Mag. of Nat. Hist.,’ do not require any correction. Its legs are 
equal in length, and the posterior pair have a calamistrum on 
the superior surface of each metatarsus. The spinners are eight 
in number ; those constituting the inferior pair, which are the 
shortest, consist of a single joint each, and are united through- 
out their entire length. The sexual organs are moderately de- 
veloped, of a red-brown hue, and have, in connexion with their 
anterior margin, a brownish-yellow process which is directed 
backwards. 
This is the only Spider provided with eight spinners and 
calamistra, belonging to the tribe Senoculina, that has come 
under my observation; and as its superior spinners are long 
and triarticulate, with the spinning-tubes disposed on the infe- 
rior surface of their terminal joint, it may reasonably be inferred 
that its economy must be influenced by its very remarkable ex- 
ternal structure. 
From the above considerations, it is evident that for the re- 
ception of this species, and also of the Gicobius domesticus and 
Cicobius annulatus of M. Lucas, should a close relation of affinity 
be hereafter established among them by similarity of organiza- 
tion, of which scarcely a doubt can be entertained, a new family 
must be founded, which may be thus characterized :— 
Family Gicosrp2z. 
Spinners eight; those of the inferior pair, which are the 
shortest, consist of a single joint each, and are united through- 
out their entire length. 
Legs of variable relative length in different species, each 
metatarsus of the posterior pair being provided with a calamis- 
trum on its superior surface. 
