Spermatogenesis in spiders. 555 



of the circle of autosomes (Fig-. 115) and it passes to one pole very 

 early in tlie metaphase, undivided. At least one of the very small 

 chromosomes may pass early to one pole but I have not determined 

 whether or not it divides at this time (Fig. 115). 



After the first division the autosomes become diffuse and form 

 a lightly staining reticulum, during which time the accessory chromo- 

 some elements retain their compact form. This constitutes a very 

 distinct rest period. During the metaphase, the accessory elements 

 divide, as in other spiders. 



Number of chromosomes. 



Counts made on flat equatorial plates of the first division, such 

 as shown in Fig. 116, give the haploid number of autosomes as 10. 

 On this basis, the chromosome constitution would be: 

 Autosomes 20 



Accessory chromosome 2 



Total 22 excluding the supernumerary bodies. 



As may be seen from the above description, Lycosa communis 



agrees in all essential particulars with the other spiders studied, 



and there seems little reason for supposing that a re-examination 



of Lycosa insopita would afford different results. 



Sperniatogeuesis of Oxyopes salticns. 



As a member of the family of Oxijopidae, the common southern 

 form was studied. The spermatogenesis of this form shows essentially 

 the same behavior of the autosomes and of the accessory chromo- 

 some which we have found in the other forms studied. In the first 

 maturation division the accessor}'' chromosome passes to one pole 

 undivided, early in the metaphase (Fig. 117). Sometimes we may 

 find attached to the accessory elements two very small bodies which 

 appear as ctetosomes. Unfortunately, both of the specimens are not 

 well preserved so that the course of the bodies could not be followed 

 through the maturation division. In equatorial view, we find 10 

 autosomes. On this basis the chromosome constitution of this form 

 would be: 



Autosomes 20 



Accessor}'' chromosome 2 



Total 22 excluding the supernumerary elements. 



