oSO John Beard, On the Life-History and Development of the Genus Myzostoma. 



Fi"- 19 M. glah-um. Larva of four days. Living. n.s.l = larvai nervous system. 

 ° p.o.c = postoral ring of cilia. p.a.c = praeanal ring of cilia. a.c = 



alimentary canal, se = larvai setae. 

 Fig 20 M. cirriferum. Larva of three days. Living. Letters as in preceding fig. 



Actual size of this and preceding larva about 0,04 mm. Zeiss D. Oc. 2. 



Fi- '>! il/, glahrum. Larva of five days. Back view. Littering as in fig. 19. 



'^ Further s.h = sense bairs of praeoral lobe, pr = proboscis. a.p.c = 



cilia of anal papilla. 

 Fig. 22. M. glahrum. Larva of five days. Length = 0,64mm. Side view. Letter- 

 ing as in figs. 21 and 19. 

 Fi«' ''3 M glahrum. Larva of six days. Lettering as above. 

 Fig.' 24.' M. glahnim. Larva of about seven days. Lettering as above. m.c - 



muscle cord. 

 Fi«-. 25. 31. glabrmn. Larva of about eight days. Killed with osmio acid. 

 Fig. 26. 31. glahrum. First postlarval stage on Comatula. One pair of legs. ap. l. 



n.s.a = adult nervous system. 

 Fig. 27, 28. 31. glahrum. Longitudinal sections in horizontal and vertical planes 



respectively of five days larvae. Zeiss E. Oc. 2. Cam. lue. 

 Fig. 29. Somewhat rough copy of Gottes figure of the larva of Nereis Dumerilii. 



Piate 32. 

 Fig. 30. Part of disc of a Comatula with large hermaphrodite 31. glahrum and 



two males. Magnified 10 times. 

 Fig 31. 31. glahrum. Sect. of skin with touch rods s.r. Zeiss D. Oc. 3. Cam. lue. 

 Fig. 32. 31. glahrum. Epidermis, str = Striae due to prolongations of cilia. 



Leitz Vis ìQ- Som. Imm. Oc 2. Cam. lue. 

 Fig. 33, 34. 31. glahrum. Male. Transverse section of nervous system. Zeiss E. 



Oc. 2. Cam. lucid. sep = septum. g.c = ganglion celi. /.:: = libroua 



zone, n.r = nerve root. ce = connective tissue. c.t.i = connective 



tissue investment. 

 Fi'' 35 31. glahrum. Male. Transverse section of alimentary canal and skm. 



B.c = body cavity. ov = partially digested ova of hermaphrodite. 



ep.g = alimentary epithelium. Hartnack 5. Zeiss Oc. 2. Cam. lue. 

 Fig. 36. Part of transverse section of hermaphrodite 31. glahrum. — ov = fully 



grown ova. y.o = young ova. c.t.i = connective tissue. Zeiss E. 



Oc. 2. Cam. lue. 



Fig. 37, 38. Transverse sections of male of JI. ^/a&nwì. Hartnack 5. Zeiss 

 Oc. 2. Cam. lue. h.c = body cavity. t = testis. a.c = alimentary 

 canal, m.c.t = mother cells of testis. le = part of foot. ^ ;^s = ner- 

 vous system, v.s = vesicula seminalis. v.à.o = male opening. 



Fig. 39. Ova of il/. 5^Za6ra»i in transverse section. Zeiss E. Oc 2. Cam. lue. 

 Ji.f.p = portions of germinai spot, p.e = protoplasm of egg. g-v - 

 germinai vesicle. g.s = germinai spot. 



Fig. 40-48. Various post -larvai stages. Mostly Zeiss E. Oc. 2. Cam. lu^. 

 Figs. 41, 44, 45, 48 probably of 31. cirriferum, not of 3/. glahrum. a.p - 

 permanent appendages. n.s = adult nervous system, s.s = segmentai 

 septa. me.c = mesoblast cells- 



Druck vou Breitkopf & Härtel in Leipzig. 



