HYDROID ZOOPHYTES. 33 
DESCRIPTION OF THE PLATES. 
KEY TO THE LETTERING OF THE PLATES. 
ac., acrocyst ; b/., blastostyle ; ¢.p., chitinous pellicle ; d., dactylozooid ; yph., gonophore ; y/h., gonotheca ; 
gz., gastrozooid; fw., hydrocaulus; Arh., hydrorhiza; hth., lydrotheca; hyd., hydranth ; 
m., manubrium; ”., node; nph., nematophore; op., operculum; ov., ovum; /p., perisarc ; 
rhe., rhizocaulus ; sp., Sperm ; sv.c., sub-umbrella cavity ; ¢., tentacle ; v., umbrella; 2., zooid. 
PLATE I. 
Fig. 1.—Perigonimus antarcticus growing on Halecium arboreum (x 2). he. H., hydrocaulus of 
Halecium arboreum; hyd., hydranth of Perigonimus ; gph., gonophore of Perigonimus. 
Fie. 2.—Perigonimus antarcticus 6 (X 20). hrh., hydrorhiza; m., manubrium of gonophore ; 
p., perisare ; sp., sperm filling the sub-umbrella cavity ; v., umbrella wall. 
Fic. 3.—Perigonimus antarcticus 9 showing variability (due to contraction) of form of the hydranths 
(x 20). he., hydrocaulus; hrh., hydrorhiza; hyd. hydranth; m., manubrium of gonophore ; 
ov., ova embedded in the ectoderm of the manubrium ; sv.c., sub-umbrella cavity ; v., umbrella wall. 
Fig. 4.—Eudendrium insigne. Hydranth (x 30). ¢., collar of deeply staining cells ; y., perisare. 
Fig. 5.—Stylactis haleciti (x 30). Outer region of colony growing on Halecium arboreum; d., dacty- 
lozooid ; he. H., hydrocaulus of Halectum; hrh., hydrovhiza ; gz., gastrozooid. 
Fic. 6.—Stylactis halecii (x 20). Central region of colony growing on Halecium arboreum ; b1., blasto- 
style ; d1.f., tentaculate blastostyle ; yz., gastrozooid ; ie. H., hydrocaulus of Halecium ; hrh. P. & C. 
hydrorhize of Perigonimus and Campanularia. 
PLATE II. 
Fie. 7.—Hydractinia dendritica encrusting Halecium arboreum (x 10).  1., blastostyle ; gph., gonophore ; 
g2., gastrozooid ; 7.sp., ridge-like spine. 
Fic. 8.—Hydractinia dendritica. Fragment of rhizocaulus (x 20). 0/., blastostyles ; gph., gonophore ; 
gz., gastrozooid ; rhe., rhizocaulus. 
Fig. 9.—Hydractinia dendritica (x 2). Young rhizocauline colony developing from the encrusting 
basal region ; enc. 7., encrusting region ; fr. riv., free rhizocauli. 
Fig. 94.—Hydractinia dendritica, encrusting Halecium arboreum (x 1). 
Fig. 10.—Hydractinia dendritica. Part of adult rhizocauline colony (x 1). r/ec., rhizocaulus ; 2., zooids. 
Fia. 11.—Tubularia longstaffi (<x 1). gph., gonophores ; frh., hydrorhiza. 
Fie. 12.—Tubularia ralphi (x 2). 
Fie. 13.—Tubularia hodgsoni (x 1). 
Fig. 14.—Lampra microrhiza (x 1). c¢.p., chitinous pellicle ; gph., gonophores ; hrh. f., hydrorhizal 
filaments. 
PLATE III. 
Fre. 15.—Lampra parvula. Young zooid (x 10). d.t., distal tentacles; /e., hydrocaulus; hrh. f, 
hyrdrorhizal filament ; iyd., hydranth ; p.t., proximal tentacles ; /.2., polyzoan colony to which the 
zooid is attached. 
VOL. Ul. DG 
