2 Mr. MacLeay on some new forms o/" Arachnida. 



Four of these species will be sufficient to show that this inter- 

 esting order has never yet been correctly marked out in any en- 

 tomological work. I am not fond of giving insulated descrip- 

 tions without an ulterior object in view ; and therefore I may 

 as well state that my aim now is to show that a time spider may 

 have a distinct head, — that spiders may have an articulated 

 thorax and abdomen, — that spiders may have only two eyes, — 

 and that those which have eight may have them disposed in 

 systems very different from any of the systems hitherto de- 

 scribed, — finally, that although spiders in general have their 

 labial palpi like feet, some species on the other hand may 

 have their true feet like palpi and their labial palpi with- 

 out ungues. Nay, were I to proceed to the other orders of 

 Arachnida, I could exhibit facts equally extraordinary with 

 respect to the whole class. For the present I shall merely 

 say that my mode of distinguishing the order of Araneidea 

 from other Arachnida is as follows : — 

 Head rarely distinct from thorax. 

 Antennae of two joints, the last of which is a moveable corneous 



fang. 

 Labrum and Mandibles confluent with the tongue so as to 



forai the oral orifice. 

 Maxillary palpi five-jointed. 

 Abdomen pedunculated ; furnished at the base with two or 



four respiratory apertures, and at the extremity with a 



spinning apparatus. 

 Feet with the coxae and tibiae each of two joints. 



Genus NOPS. 

 Antenna:'^ small, not advancing from under the head, the first 



abdomen is furnished with a spinning apparatus. Nor are the four cha- 

 racters given to the order by Walckenaer (Hist. Nat. des Ins. Apt. vol. i. 

 p. 38) less liable to objection. 



* Walckenaer asks what is the use of calling these organs chelicera or 

 antennae. The answer is, that if we give them the old name " mandibles," 

 we are decidedly wrong ; and that if we call them antennae, we refer them to 

 those organs of Ptilota with which they correspond by analogy of position. 

 If we dissect a large Nephila when alive, we can easily perceive that these 

 organs are not in the mouth, but separated from it by the labrum, which is 

 under them, and not above them as Walckenaer erroneously says. The fact 

 is, that the part which is called by Walckenaer the " bandeau" is not the true 

 labrum, which is confluent with the mandibles, so as to form what the French 

 call the " langtiette" 



