476 EXPLANATION OF THE LETTERING. 



g.h Cephalic gastro-hepatic gland. 



g.i . Intraganglionic infolding of the middle cord. 



g.iv. Invagination for optic ganglia. 



gm.c Germ cells. 



g.n.c Gustatory nerve roots. 



g.o. Gustatory organs; genital organs. 



g.p. Gular plates. 



gr. . . Groove between olfactory organs. 



gt.p Gut pouch. 



g.tr Gustatory tracts. 



gust.n Gustatory nerve. 



gust.o Gustatory organ. 



g.w. Germ wall. 



h. . . . . Hypodermis. 



h 1 " 2 . . Bony plates covering the hyoid arches. 



H.as Hemisphere association cells. 



H. as.tr ....... Hemisphere association tracts. 



h.c Haversian canals; hepatic caeca. 



he ... Hydrocoele. 



h.co Haemal commissures. 



h.l. Haemal lamina of cephalic shield. 



h.m Hyo-mandibular. 



h.m.n. ... Hyo-mandibular line of canal organs. 



h.n.c . . . . .Haemal nerve cord. 



h.ne.n Haemo-neural nerve. 



h.n.m . Haemo-neural muscle. 



h.pr . Haemal processes. 



h.r 1 " 5 Haemal roots. 



h.ri .Horn ridges. 



h.s. . . Tergal plates of the abdominal half-segments. 



hst Haemostoma. 



ht... Heart. 



h.tr. . Haemal tracts. 



hy. . . . Hyoid. 



hyp. ... Hypophysis. 



i Intestinal nerves (i-io). 



i.ent. . . Inter-entapophysial muscle. 



i.g ... . Inter-ganglionic infolding of the middle cord. 



i.g.s. . Inter-ganglionic spaces. 



i.l.m. . . . .Gill muscle. 



i.n.l. . Inner neurilemma; neuroglia. 



int Intestinal nerve. 



i.og. . . .Post-oral or mesocephalic neuromeres. 



i.o.l. ... .Infra-orbital line of canal organs. 



i.p. . . .Internal pores. 



i.pl. . . .Intestinal plexus. 



i.r .Transverse ridge-plate on inner surface of the premaxilke 



i.sh. . . Inner neurilemma sheath. 



i.v Infoldings leading to neural canal. 



iv.l.e.g Invagination for lateral eye-ganglion. 



iv.ol.l Invagination for olfactory lobes. 



