548 Theophilus s. Painter, 



the spindle (Fig. 90). In the case of the very small chromosome 

 I have been able to trace its course through the division. It does 

 not divide and cells have been observed in which it went to the 

 side which had received the accessory chromosome, and cells which 

 did not receive the latter body. Its distribution seems to be a 

 matter of chance. In the case of the other two bodies, only one of 

 which is shown in Fig. 90, I have not followed their course in 

 detail, but there is no reason for thinking that their behavior is 

 different from that of the smaller body. 



Second maturation division. 



The accessory chromosome divides early in the second division. 

 The course of the small planosomes has not been traced but they 

 do not lag behind in the spindle after the autosomes go apart. 



The equatorial plates of this form are unusually flat for spiders 

 and there is little or no over-lapping. Seven flat plates were counted, 

 such as shown in Fig. 88 or 89, and they all gave the same number 

 of autosomes, which is ten. On this basis the somatic number would 

 be as follows: 



Autosomes 20 



Accessory chromo some 2 



Total 22 excluding the planosomes. 



Spermatogenesis of Limjphia jnarginata. 



Only one specimen of this form has been studied, and it was 

 too immature to show any spermatocyte divisions. But cells in all 

 phases of the growth period were found, and these agree in evei-y 

 detail with the behavoir found in the other forms studied. During 

 the pachytene stage the accessory chromosome elements appear as 

 two rods taking the stain very deeply. There were no indications 

 that a planosome was present in this specimen. 



Counts made on spermatogonia! cells would indicate that the 

 chromosome number was low, probably about 10 for the haploid 

 number. 



Spermatogenesis of Bpeira sei'icata (sclopetaria), 



Epeira sericata has been studied as a member of the highly 

 specialized family of Ärgiopidae. This is the same species worked 



