Spermatogenesis in spiders. 547 



are very small and furthermore, no killing- fluid has been found 

 which would give good preservation. Two species were sectioned, 

 Fholcus pJialangoides, a very common form all over the country, 

 and SpermapJiora meridionalis, which is a common house spider in 

 Virginia. 



It has not been possible to follow the history of the germ cells 

 in any detail for the Spermaphora. In the first maturation division 

 the accessory chromosome appears to be made up of two elements 

 and these pass undivided to one pole (Fig. 85). No planosomes have 

 been observed at this division. The spermatids are of two kinds; 

 part of them carry the accessory chromosome elements and part 

 lack them. Thus the Pholcidae fall in line with the rest of the 

 spiders, in this respect. 



Spermatogenesis of CaUilejns inibecilla. 



The Drassidae are usually considered by arachnologists as being 

 a primitive family of spiders. The representative of this group which 

 was studied, was the common species Callilepis imbecilla. Only one 

 specimen was studied, but this has given an abundance of matu- 

 ration division stages. Spermatogonial divisions are lacking from 

 the material. 



First maturation division. 



The general processes going on during the growth period are 

 closely similiar to those found in Maevia vittata. The pachytene 

 stage does not show any marked "bouquet" formation; however, we 

 often find lying free among the threads of this period as many as 

 three small densely staining bodies, in addition to the accessory 

 chromosome elements (Fig. 86 P). Practically all of the cells show 

 these bodies, though a varying number is seen. 



The spindle of the first maturation division shows the accessory 

 chromosome as two very long rod-like elements lying outside of the 

 general circle of autosomes (Fig. 87). The relative size of the 

 accessory bodies as compared with the autosomes is larger than in 

 any other form studied. In equatorial view (Figs. 88 and 89) the 

 accessory may be seen in cross-section. 



Early in the metaphase, the accessory chromosome passes 

 undivided to one pole of the cell; the autosomes divide and as 

 they go apart we find several small chromosomes lagging behind in 



