44O ARACHNIDA PODOGONA PHALANGIDEA CHAP. 



than previous writers, are of the opinion that they ought to 

 constitute a separate order of Arachnids, more nearly allied to 

 the Pedipalpi than to the Phalangidea. In this place it is 

 only possible to indicate some of their peculiar characteristics. 

 Their integuments are particularly hard and coriaceous. The 

 cephalothorax is united to the abdomen by a rather broad 

 pedicle, but there is also a remarkable coupling apparatus which 

 makes the constriction between cephalothorax and abdomen appear 

 very slight. There is a movable anterior projection of the 

 cephalothorax, the " cucullus." The two - jointed chelicerae 

 terminate in minute chelae, as also do the five-jointed pedipalps. 

 There are no spiracles on the abdomen, but two are situated on 

 the thorax above the coxae of the third pair of legs. Perhaps 

 the most remarkable fact is that, as in the Araneae, a modified 

 limb is used by the male for the fertilisation of the female ; but in 

 this case it is not the tarsus of the pedipalp, but of the third leg of 

 the male, which is specially developed as an intromittent organ. 

 Ordinal rank is not universally accorded to the group, but 

 whatever its true position, the known forms fall under a single 

 family Cryptostemmatidae, including the two genera Crypto- 

 stemma and Cryptocellus. 



Order VIII. Phalangidea (Opiliones). 



Tracheate Arachnids, with abdomen united to the cephalo- 

 thorax by its whole breadth. They are oviparous, and undergo 

 no metamorphosis. Abdomen always segmented. A pair of 

 odoriferous glands opening on the thorax. Two simple eyes; 

 three-jointed chelate chelicerae ; pedipalpi not chelate. Spinning 

 organs absent. 



" Harvesters," " Harvestmen," or " Harvest-spiders/' as these 

 animals are popularly called, need never be confounded with true 

 Spiders if the absence of a constriction between the cephalo- 

 thorax and abdomen be noted. They are more difficult to dis- 

 tinguish from Mites, members of which group have sometimes 

 been described as Phalangids. The Phalangid is, however, 

 generally recognisable by its segmented abdomen, and as a 

 further point of distinction, it may be noted that, whereas the 

 anal orifice is always transverse or circular in Phalangids, it is 

 uniformly longitudinal in the Acariiies. 



