ARACHNIDES, 27® 



FAMILY I. 



ARANEIDES. 



This family is composed of the genus Aranea, Lin., or the Spiders. 

 They have palpi resembling little feet, without a forceps at the end, 

 terminated at most in the females by a little hook, and the first joint 

 of which, in the males, gives origin to various and more or less com- 

 plicated sexual appendages*. Their frontal chelicerse (the mandibles 

 of authors) are terminated by a moveable hook, flexed inferiorly, 

 underneath which, and near its extremity, which is always pointed, is 

 a little opening, that allows a passage to a venomous fluid contained 

 in a gland of the preceding joint. There are never more than two 

 jaws. The ligula consists of a single piece, is always external and 

 situated between the jaws, and either more or less square, triangular, 

 or semicircular. The thoraxf usually marked with a depression in 

 the form of a V, indicating the space occiqjied by the head, consists of 

 a single segment, posteriorly to which, by means of a short pedicle, 

 is suspended a moveable and usually soft abdomen ; it is always fur- 

 nished, under the anus, with from four to six closely approximated 

 cylindrical or conical articulated mammillae with fleshy extremities, 

 which are perforated with numberless small orificesj for the passage 

 of silky filaments of extreme tenuity proceeding from internal reser- 

 voirs. The legs, identical as to form, but of diff"erent sizes, are com- 

 posed of seven joints, of which the two first form the hip, the third 

 the thigh, the fourth § and fifth the tibia, and the two others the 

 tarsus : the last is terminated by two hooks usually pectinated, and in 

 several by one more, which is smaller and not dentated. The intes- 

 tinal canal is straight, consisting of a first stomach composed of 



* From all the observations that have been made on the mode of copulation of the 

 AraneiJes, I am still inclined to believe that these appendages are the genital organs. 

 I have vainly sought for particular organs on the base of the abdomen of a large male 

 Mygale preserved in spirits. We are not always to judge from analogy ; for the 

 sexual organs in the female Glomcris, Julus, and other Chilognatha, are situated near 

 the mouth, a fact of which no second example is to be found. 



f The term cephaJo-thorax would be more strict and proper ; not being in use, 

 however, I have thought it best to avoid it ; neither will I employ that of corselet, 

 although generally admitted, because, with respect to the Coleoptera, Orthoptera, 

 &c., it only applies to the prothorax or first thoracic segment. 



X These holes are pierced in the last segment, which is frequently retracted. 

 If it be strongly compressed, very small mammilla, (at least in some species,) perfo- 

 rated at the extremity, are protruded — they are the true fusi or spinning apparatus. 

 Some naturalists think that the two smaller mammilla;, situated in the middle of the 

 four exterior ones, furnish no silk. 



§ This joint, or the first of the tibia, is a kind of patella. 



