410 
KATHI.EEN HADDON. 
13. Steenstrup. — ‘ Oversigt over (let K. Danske Vid. Selskabs For- 
liandlinger,’ 1869-70. p. 179. 
EXPLANATION OF PLATE 22, 
lllustratiiijr Kathleen Hadden’s paper on “ Herpyllol)ius 
a r c t i c u s .” 
Fig. 1. — Adult female on Harmotlioe imbricata, showing the 
attachment of the parasite to the dorsal surface of the worm's head. 
Fig. 2. — Dorsal view of an adult female, showing two males attached 
posteriorly. On either side of these are the chitinous buttresses 
supporting the egg-sacs. 
Fig. 3.— Side view of a stained specimen after clearing; external 
portion of the parasite only. The oi^aque gut lies in the centre sending 
out radiating channels. Posteriorly is showm a chitinous buttress for 
the support of an egg-sac. 
Fig. 4. — Longitudinal section through an adult female. 
Fig. 5. — Side view of the peculiar type, after staining and clearing, 
showing the arrangement of the genital organs. 
Fig. 6. — Transverse section of the above specimen. 
Fig. 7. — Transverse section of a normal female, showing the external 
I^ortion, and the root embedded in tissiies of the host. 
Fig. 8. — Transverse section of wmrm’s head, showing space {s}).) 
formerly occupied by the roots of the parasite. This pierces the 
cerebral ganglion of the worm. 
Fig. 9. — Transverse section of the same worm farther back, with the 
root of the parasite (rt.) lying beside the oesophagus of the worm. 
Fig. 10. — Dorsal view of a male Herpyllobius enclosed in its last 
larval skin. 
Lettering. 
h. Buttress supporting egg-sac. ca. Canal system of body. eg. Cere- 
Imal ganglion, co. Commissure. C7it. Cuticle, czth' Cuticle of root. el. 
Elytra of worm. ep. Epidermis of worm. es. Egg-sac. fib. Fibrous 
tissue, gl. Glandular oviduct, g.o. Genital opening. Uf. Hold-fast. 
Jiij 27 . Hypodermis. lac. Lacunar system of root. l.v. Lateral vesicle. 
m. Mouth, mb. Membrane formed by worm. m.f. Muscle-fibres, mth. 
Mouth of worm. m.v. Median vesicle, od. Oviduct, ces. (Esophagus. 
ov. Ovum. par. Parapodium. rt. Root of parasite, s. Space occupied 
by parasite. sp. Spermatonliore. sp. d. Duct of spermatophore. 
t. Telson. v. n. c. Ventral nerve- cord. 
