20 
List of Literature. 
Boas, I. E. V. — Bidrag til Pteropodernes Morfologi og Systematik. — Spo- 
lia Atlantica. — Kgl. Danske Vidensk. Selsk. Skr. 6 R., nat. & 
math. Afd. IV, 1. — Kbh. 1886. 
Chun, C. — Bericht iiber eine nach den Canarischen Inseln im Winter 
1887/88 ausgefiihrte Reise. — Sitz.-ber. d. konigl preuss. Akad. 
d. Wissensch zu Berlin. Jahrg. 1889. 
Clarke, S. F. — The Hydroids. — “Albatross” East Pacific Exp. 1904-05. 
— Mem. Mus. Comp. Zool. Harvard Coll. Vol. XXXV, No. 1. 
1907. 
Fewkes, I. W. — On certain Medusæ from New England. — Buil. Mus. 
Comp. Zool. Harvard Coll. Vol. XIII, No. 7. 1888. 
Jaderholm, E. — On some exotic Hydroids in the Swedish Zoological 
State Museum. — Arkiv for Zoologi. Bd. 13, No. 3. 1920. 
Jungersen, H. F. E. — On a new Gymnoblastic Hydroid ( Ichthyocodium 
sarcotretis ) epizoic on a new Parasitic Copepod ( Sarcotretes 
scopeli) infesting Scopelus glacialis Rhdt. — Naturhist. Foren, 
vidensk. Medd. Bd. 64. København 1911. 
LI oyd, R. E. — Nudiclava monocanthi, the Type of a new Genus of Hy¬ 
droids parasitic on Fish. — Rec. Indian Museum. Vol. I, Part 4. 
1907. 
Steche, O. — Bemerkungen iiber pelagische Hydroidenkolonien. — Zoolog. 
Anzeiger. Bd. 31. 1907. 
Stechow, E. — Hydroidpolypen der japanischen Ostkiiste. I, — Beitr. z. 
Naturgesch. Ostasiens. — Abh. math.-phys. Klasse d. K. Bayer. 
Akad. d. Wiss. I. Suppl.-Bd. 6. Ahb. Miinchen 1909. 
Tesch, J.J. — Pteropoda. — Das Tierreich. Lief. 36. Berlin 1913. 
Van hoffen, E. — Die Hydroiden der Deutschen Siidpolar-Expedition 1901 
—1903. — Deutsche Siidpolar-Exped. Bd. XI. Zool. III. 1910. 
Warren, E. — On Hydrichthys boycei, a Hydroid parasitic on fishes. • - 
Ann. Durban Mus. Vol. I. 1916. 
Explanation of Plate I. 
List of abbreviations. 
b. c. bell cavity. 
c. v. circular vessel. 
end. 1. endoderm lamella. 
ex. exumbrella. 
/. fold (at the base of the hydranth). 
ir. p. interradial pouch of bell cavity. 
