262 RICHARD ASSHETON. 



Fig. Y. — A stage found in Ovis, and by hypothesis common to many other 

 mammals. The hypoblast is doubled over one pole. 



Fig. Z. — A typical mammalian blastodermic vesicle interpreted according 

 to the specimens figured on Plate 2 of this paper, supposed to be common to 

 many mammals besides the sheep. 



Figs. Tj — T4. — Four diagrams illustrating the interpretation according to 

 the hypothesis of some of the succeeding stages of the development of the 

 mole (Talpa europsea). Compare Heape (30), figs. 18, 23, 26, 27. 



Figs. Ttj — TUo. — Three diagrams illustrating the stages subsequent to Z of 

 Tupaia javanica. Compare Hubrecht (36), figs. 16, 23, 33, 41, 62, 68, 

 with diagrams X to Tv^. 



Figs. Sd — SU5. — Six diagrams illustrating the stages subsequent to Z of 

 Sus scrofa. Compare Assheton (5), figs. 19, 31, 39, and Keibel (40), 

 and figs, on Plate 17 of this paper. 



Figs. L — L4. — Five diagrams illustrating the stages of tlie rabbit (Lepus 

 cunicula) subsequent to Z. 



Figs. Ei — E^. — Four diagrams illustrating the stages subsequent to W of 

 Erinaceus interpreted according to hypothesis. Compare with Hubrecht (33), 

 figs. 25, 39, 15, 20 b, 51, 49, &c. 



PiQS. V — V7. — Eight diagrams illustrating the development of Vespertilio. 

 Compare figs. W, V, with Duval (26), figs. 15, 21, fig. Vj with Van Benedeu 

 and Julin (13), fig. 6, and Y—Yy with Duval (26), figs. 33, 36, 41, 50, 76, 102. 



Figs. Mj — Mj. — Five diagrams of Mus. Compare with Robinson (46), 

 figs. 4, 6, 8, 10, 13. 



i'lGS. Cj— C4. — Four diagrams of Cavia. Compare with Seleuka (49), 

 pis. xi, xii, figs. 1, 3, 9, 13. 



