Kaiharine Foot and E. C. Strobell 229 



Annelids. He says : " I am convinced that this peculiar body is homolo- 

 gous with the problematical lobe which is described by Mead, '95, in the 

 egg of Chcctoptcrus and further it is probably identical with the pohir 

 rings observed by Wliitman, '78, in Clepsine and since then by various 

 authors in different Annelids." 



Comparisons with Other Annelids. 



In the oogenesis of Annelids there has been very little work done on 

 the prophases of the first maturation spindle. 



Among the Lvmhricidae we have not found any record of observations 

 on these stages, but in the spermatogenesis of Lnmhricus terrestris 

 Calkins, '95, has studied the prophases of the first division and the two 

 species, AUolohophora and Lumhricus, are in accord in showing a spireme 

 with a longitudinal furrow. In Lumhricus, however, the spireme divides 

 transversely into the full number of somatic chromosomes, and there is, 

 therefore, no numerical reduction of the chromosomes by two univalent 

 chromosomes remaining attached end to end as in AUolohophora. 



In the first spindle of Lumhricus there are sixteen tetrads, the 

 spermatocytes second order receiving each sixteen double chromosomes. 

 Calkins adds : " Whether this is a reducing division in Weismann's 

 sense cannot be ascertained." 



Vejdovsky's and Mrazek's recent valuable work, '03, on Rhynchelmis 

 is confined to later stages, the material being unfavorable for the study 

 of the prophases of the first maturation spindle. Of these stages they 

 say : " Das Studium der ersten Vorgange der Eireif ung ist schon tech- 

 nisch sehr zeitraubend, wenn man auf den endlosen Schnittserien durch 

 die einige Zentimeter langen von Eiern prall angefiillten vorderen 

 Abschnitte des Wurmleibes stets nur entweder noch ruhenden Kernen 

 oder den bereits fertigen Eeifungsspindeln begegnet" (pp. 454 and 455). 

 They have, however, supplemented their work on Rhynchelmis by a 

 study of the prophases of the first spindle in Tuhifex, Limnodrilus and 

 Ilyodriliis, but their results are demonstrated by a single text figure 

 showing a germinal vesicle with tetrads. In explanation of this figure 

 they say : " Den ganzen Vorgang der Chromosomenbildung konnten wir 

 nicht verfolgen. Erst in spateren Stadien fanden wir die in Textfigur 3 

 abgebildeten Formen der Chromosomen. Es sind dies Gebilde, die wie 

 aus zwei dicht an einander gelegten sichel- oder biskuitformgen Teilen 

 zusammengesetzt erscheinen. Ein Vergleich mit den an anderen Ob- 

 jekten gewonnenen Eesultaten fiihrt zu dem Ergebnisse, das wir hier 

 langsgespaltene doppelwertige Elemente vor uns haben, die den typischen 



