52 SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. IIO 



Glands contained in the pedipalp coxae and opening into the preoral 

 food cavity are said to be present in all members of the Araneida; 

 they are known as the salivary glands, or "maxillary" glands. Accord- 

 ing to Petrunkevitch (1933) these glands are unicellular in Hypo- 

 chilus, but in all other genera they are multicellular sacklike organs, 

 the number in each coxa varying with the species. In Liphistius and 

 the Mygalomorphae the glands, as shown by Bertkau (1885) in 

 Atypus, are distributed along the entire length of the coxa, and open 

 irregularly on the upper surface near the inner edge. In other spiders 

 the glands open on a small oval or circular area on the inner face of 

 each coxa, known as the "sieve plate" because of its perforation by 

 the duct orifices. A gland, or pair of glands, is present also in the 

 labrum. The structure of the labral gland in Atypus piceus Sultzer 

 is described in detail by Bertkau (1885), who says the gland opens on 

 the outer surface of the labrum. According to Petrunkevitch (1933) 

 there is apparently a pair of labral glands ("rostral glands") in all 

 spiders, but in some they are so closely united as to appear to be a 

 single organ. The two ducts discharge into a wide, slitlike atrium that 

 opens to the exterior. 



In the feeding of the spiders, extraoral digestion plays an important 

 part. A powerful digestive fluid from the stomach is discharged on 

 the prey and completely liquefies the soft tissues. So copious and 

 effective is this exuded digestive fluid that some spiders are able to 

 consume even small vertebrates, which they kill by the venomous bite 

 of the chelicerae. In recording observations of the feeding of Palystes 

 natalius (Karsch), a South African member of the Heteropodidae, 

 on a small lizard, Warren (1923) says: "All the ordinary tissues, 

 including tendons and cartilages, were rapidly softened, and the body 

 became plastic, while the bones were completely disarticulated. The 

 voluntary muscles and all the softer tissues dissolved with great 

 rapidity when the out-flowing and in-flowing currents of digestive 

 fluid gained access to them. After a period of about two and a half 

 hours the body (about if in. long) of the lizard had been reduced to 

 a small, blackish, rounded and somewhat dry mass about ^ in. in 

 diameter. This mass the spider allowed to drop to the ground." 

 Abraham (1923) records the feeding of a species of Thalassius, 

 family Pisauridae, on live fish, small frogs, and tadpoles. He describes 

 the catching of fish in an aquarium by the spider, which holds to a rock 

 by its long hind legs and plunges into the water to seize its victim. 

 Baerg (1938) says of a large species of Dugesiella (Aviculariidae) 

 that in captivity it will feed on recently killed animals, "accepting 



