522 THE ANIMAL KINGDOM. 



end with the oviduct ; and two uteri, with a single short muscular vagina. 

 Ciliated epithelium is found in the ducts of the receptaculum, and in the 

 section of the vas deferens that secretes the spermatophore. 



In P. Novae-Zealandiae the tracheae are said to branch. The end 

 of the male duct is exceedingly muscular (= penis?), and contains uni- 

 cellular glands in its walls. There is a spermatophore (Moseley). 



The various species of Peripatus are found at the Cape of Good Hope, 

 in Australia and New Zealand, in Central and South America, and the 

 West Indies. They live under stones, in rotting wood, &c. in moist places, 

 are nocturnal in habit, and feed on insects, &c., which they ensnare by 

 the ejection of slime from the oral papillae. Their distribution and 

 anatomy point to an extreme archaic origin. 



Moseley, ' Myriapoda,' Encyclopaedia Britannica (ed. ix), xvii ; Balfour, Q. J. M. 

 xxiii. 1883 (with lit.); Gaffron, Schneider's Zool. Beitrage, i. 1885. Eye, Carri&re, 

 'Sehorgane der Thiere,' 1885, p. 121. Development, Sedgwick, Q. J. M. xxv. 1855; 

 xxvi. 1886; von Kennel, Arb. Zool. Zoot. Inst. Wurzburg, vii. 1885; viii. (i), 1886. 



CLASS ARACHNID A. 



Tracheate or branchiate Arthropoda with a cephalothorax bearing 4-6 

 pairs of ambulatory limbs, and an abdomen either segmented or unsegmented 

 and sometimes divisible into two distinct regions, an anterior mesosoma, and 

 a posterior metasoma, with a post-anal telson or spine. 



The head is rarely distinct from the thorax (some Acarina}, or the 

 thorax broken up into three clearly separate somites {Solifttgae), In 

 tracheate forms the abdomen may be soft, unsegmented, and separated 

 by a constriction from the cephalothorax (Araneidae}, or else united to it 

 (Acarina}. It is scarcely represented in Tardigrada. It possesses six 

 somites in Phalangidae, in the remaining groups nine to twelve. Of 

 these the first seven in Scorpionidae or nine in Thelyphonus (Pedipalpi) 

 are broad, while the other five (Scorpionidae} or three (Thelyphonus] are 

 contracted. Among branchiate forms Limulus (Xiphosurd) has the 

 mesosoma and metasoma fused and the original segmentation lost ; the 

 Eurypterina possess twelve distinct somites, whilst the Trilobita have 

 a mesosoma containing 1-26 somites, and a metasoma or pygidium with 

 somites undifferentiated. The telson is present in Xiphosura and Euryp- 

 terina, and in the Scorpionidae, where it forms the ' sting ' and incloses 

 a poison gland. In Thelyphonus it is represented by a long jointed fila- 

 ment, and in Araneidae by a small caudal lobe or anal valve. The 

 Linguatulina differ remarkably from other Arachnida, and have an elongated 

 ringed body, sometimes flattened, with an anterior pair of sensory papillae, 

 and two pairs of chitinoid hooks placed anteriorly close to the mouth. 



