158 WHEELER. 



EXPLANATION OF PLATE V. 



{Xiphidium ensife7-ti7n. Figs. 42-46, 48-50. X. fasciatum, Figs. 47 and 51.) 



Fig. 42. Tip of abdomen in surface view from a J embryo which lias just 

 passed the lower pole. (Stage J, Fig. 9, PI. I.) t^-t.,^ fifth to eighth abdominal 

 stigmata ; ts., testis ; m.d., vas deferens ; ta.m., terminal ampulla ; ap.,^ appendages 

 of eighth abdominal segment; st. (apJ^), stylets (appendages of ninth abd. seg.; 

 ap.,^° appendages of tenth abdominal segment, in the cavities of which the 

 ampullae lie in this stage ; cc. {ap.,") cerci.; prd., proctodeum ; ««., anus. 



Fig. 43. Tip of abdomen in surface view from a $ embryo somewhat older 

 than the one shown in Fig. 42. Letters same as in Fig. 42. 



Fig. 44. Tip of abdomen in surface view from a $ embryo somewhat older 

 than the one shown in Fig. 43. v., yolk ; a^., last abdominal ganglion. Re- 

 maining letters as in Fig. 42. 



Fig. 45. Vasa deferentia (m.d.), with their terminal ampullae {ta.tn.), from an 

 embryo just before the development of the larval cuticle. 



Fig. 46. Tip of abdomen of a ^ embryo ready to hatch. Letters same as in 

 Figs. 42-44- 



Fig. 47. Tip of abdomen opened and seen from within from a J larva i cm. 

 long. t?i.o., sexual orifice, c.n., connectives ; remaining letters as in Figs. 42-44. 



Fig. 48. Tip of abdomen of J embryo in a stage corresponding to that 

 represented in Fig. 42. ov., ovary ; f.d., oviduct ; ta.f., terminal ampulla ; m.d., 

 vas deferens and terminal ampulla of the male type, still persisting ; t.^-t.,^, sixth 

 to eighth abdominal stigmata; rt/.,^ persisting appendage of the seventh abdominal 

 segment ; <?/.' (ap.^), op.^ {ap})., op.^ (ap-^°), three pairs of abdominal appendages 

 which become the gonapophyses (ovipositor) ; an., anus ; cc. {ap-"), cerci ; v., yolk. 



Fig. 49. Tip of abdomen of 9 embryo seen in full surface view in Fig. 10. (A'), 

 PI. I. mnd., location of median cord neuroblast ; cm., posterior commissure ; en., 

 connective ; ag., last abdominal ganglion. Other letters as in Fig. 48. 



Fig. 50. Tip of abdomen of 9 embryo ready to hatch. Letters same as in 

 Figs. 48 and 49. 



Fig. 51. Tip of abdomen of 9 larva i cm. long, opened and seen from within; 

 all the parts being dissected away except the reproductive organs. V£:, vagina ; 

 op.^ (ap.^), op? (ap.^), op.^ {ap-^°), three pairs of gonapophyses. Other letters as 

 in Fig. 48. 



