234 J. F. Mc Clendon, Further studies oa the Gametogenesis of Pandarus etc. 
fact that the sea-iirchin Q crinoid cf hybrid showed oiily maternal cha- 
racters? Certainly the crinoid is not distinguished from the sea-urchin 
nierely by tlie absence of characters. It is very doubtful whether all 
inheritance is Mendelian. and Godlewski’s experiment does not disprove 
the hypothesis that the clironiosomes bear some of the Mendelian factors. 
It has not been demonstrated that the characters of the sea-urchin or 
crinoid larvae obey Mendelian laws, and the purely maternal character 
of the hybrid might be explained on the groiind that the stränge Sperma- 
tozoon did not hnmediately affect the Organization of the egg. Texxant 
produced hybrid echinodemi larvae showing only paternal characters 
by decreasmg the alkalinity of the sea water. 
Explanation of Plate. 
Fig. 18 was dravsTi with the eamera lucida with Zeiss apochr. homogen, ob. 2 mm, 
oc. 4; figs. 6 — 8 and 14 with oc. 12; the remainder with oc. 18 and reduced 1/3. Figs. 1 
to 21 are from Pandarus sinuatus Say; fig. 22 is from Orthagorisdcola muricata Kröyer. 
Fig. 1. Spermatogonium. 
Fig. 2. Primary spermatocj'te, leptotane stage. 
Figs. 3 — 6. Primary spermatoc^rie, sjmezesis stage. 
Figs. 7 — 8. Primary spermatocjrie, diplotane stage. 
Figs. 9 — 10. Primär}’ spermatocyte, formation of tetrads. 
Figs. 11 — 12. Primär}’ spematocyte, first maturation mitosis. 
Fig. 13. Secondary’ spermatocyte, second maturation mitosis. 
Fig. 14. Primary oocyte, leptotane stage. 
Fig. 15. Primary ooc}’te, s}’nezesis stage. 
Fig. 16. Primary ooc}’te, diplotane stage. 
Figs. 17 — 18. Primary oocyte, growth period. 
Fig. 19. Primary’ oocyte, first maturation mitosis, prophase. 
Fig. 20. Primary ooc} te, first maturation mitosis. 
Fig. 21. Secondary’ oocyte, second maturation mitosis. 
Fig. 22. Primary oocyte, first maturation mitosis, side view of equatorial plate. 
