ZOOLOGY AND BOTANY, MICROSCOPY^ ETC. 885 



Anatomy of Spiders.* — Dr. M. Bertkau deals principally with the 

 anatomy and histology of the digestive tract which is described in 

 some detail ; the various glands in connection with the alimentary 

 system are also treated of, and tliere are some interesting notes upon 

 the so-called coxal glands which have lately been described by 

 Lankester in the king crab ; these glands were erroneously supposed 

 by Wassmann and others to be salivary glands, but it appears that 

 they have in reality no relation to the digestive system. In Atypus 

 the coxal gland of either side extends from the hinder end of the 

 cephalothorax as far as the base of the first pair of legs, and is im- 

 bedded in the lateral prolongations of the endoskeleton between its 

 two upper wing-like processes ; the posterior extremity of the gland 

 is prolonged into the fourth pair of legs together with the stomachal 

 diverticulum ; there is, however, no aperture uniting the two. The 

 whole gland is covered by a layer of longitudinal and transverse 

 fibres which unite into a cup-like structure attached to both body 

 walls between the dorsal surface and attachment of the legs; the 

 gland tissue projects for a short way into these cup-like structures ; 

 the gland itself is much coiled within its sheath. In the group of the 

 Tristicta the gland forms a simple tube not at all coiled. No external 

 aperture was discoverable in adult examples, but in young specimens 

 of Atypus the gland was found to open on to the exterior between the 

 dorsal part of the integument and the base of the third pair of legs. 

 The coxal glands are clearly a rudimentary organ and since their 

 secretion is cast out on to the exterior of the body, they are excretory 

 organs in the wider sense of the word. Perhaps the prolongations of 

 the gland towards the exterior, already referred to, are indications of a 

 metameric arrangement, in which case its analogy with the " segmental 

 organs " becomes more conspicuous. The disposition of the coxal 

 glands has some bearing upon the classification of spiders ; the fact 

 that they are always comparatively complicated (through folding) in 

 the Tetrasticta seems to show that this gi*oup is a natural one ; and 

 in the same way the Tristicta all agree in having a simple unfolded 

 coxal gland. Since the gland must be considered as a rudimentary 

 organ its less complexity in the Tristicta indicates that the group 

 should be placed lower in the system than the Tetrasticta. 



Anatomy of Epeira.t— W. Schimkewitsch gives a detailed account 

 of the anatomy of this spider. After a brief historical introduction 

 the author describes in order the various organs of the body, comparing 

 their structure with that of other Arthropoda. The eyes, previously 

 investigated by Grenacher and Graber as well as others, are described, 

 and the results given tend to show that Grenacher's description is more 

 accurate than Graber's ; tlie dimorphism of the eyes discovered by the 

 first observer is remarked upon ; the study of the central nervous 

 system and its branches shows that the " antenna) " of insects are not 

 represented in spiders ; the rostrum in spiders corresponds to the 



• Verb. (3. Naturhist. Vereins d. Preuss. Rheinlande u. Westfalens, xli. 

 (1884) pp. 66-77. 



t Ann. Sci. Nat. (Zool.), xvii. (1884) 94 pp. (8 pis.). 



