LITERATURE OF THE HYDROMEDUSAE 57 



fined to the lower surface of the colony, including numerous gastro- 

 zooids. 



FAMILY 17. STEPHALIDAE. Genera Stephalia, Hkl. ; Stephonalia, 

 Hkl. FAMILY 18. RHODALIIDAE. Genera Auralia, Hkl. ; Rhodalia, 

 Hkl. ; Angelopsis, Fewkes. 



SUB-ORDER 5. CVSTONECTAE. 



Definition. Siphonophora with an apical hollow pneumatophore, 

 without nectophores or bracts. Gastrozooids generally numerous, 

 arranged either on the lower side of the pneumatophore, or on a long 

 tubular coenosarc. 



FAMILY 19. CYSTALIIDAE. Genus Cystalia, Hkl. FAMILY 20. RHIZO- 

 PHYSIDAE. Genera Aurophysa, Hkl. ; Cannophysa, Hkl. ; Linophysa, 

 Hkl. ; Nectophysa, Hkl. ; Pneumophysa, Hkl. ; Rhizophysa, P4r. Les. ; 

 Pterophysa, Studer ; Pleurophysa, Fewkes. FAMILY 21. SALACIIDAE. 

 Genus Salacia, Hkl. FAMILY 22. EPIBULIDAE. Genera Epibulia, Esch. ; 

 Angela, Less. FAMILY 23. PHYSALIIDAE. Genera Alophota, Brandt ; 

 Arethusa, Hkl. ; Physalia, Lamk. ; Caravella, HkL 



Incertae sedis. 



(Hydromedusae which are not referable to any known order of the 

 group.) 



Limnocodium, Allm. ; Limnocnida, Gunth. ; Protohydra, Greef ; 

 Microhydra, Potts ; Tetraplatia, Busch. 



LITERATURE OF HYDROMEDUSAE. 



As far as possible only one paper on each special subject has been cited, in 

 which the student will find references to the earlier literature. 



The general subject : 



1. Allman. Monograph of the Gymnoblastic or Tubularian Hydroids, 1871-72. 



2. Allman. Chall. Rep. Zool. vii. (Hydroidea, pt. i.); xxiii. (Hydroidea, 



pt. ii.). 



3. Chun. Bronn's Klassen und Ordnungen des Thierreichs. Coelenterata, 



1889 (in progress). 



4. Haeckel. System der Medusen, 1879-80. 



5. Hacckcl. Chall. Rep. Zool. iv., Deep Sea Medusae, 1882. 



6. Hertwiij. Organismus der Medusen. Denkschr. Gesell. Jena, ii. 1878. 



7. Hincks. British Hydroid Zoophytes, 1868. 



8. Jackson. Forms of Animal Life, pp. 745-780, 1888. 



9. Lankester. Encyclopaedia Britannica, ed. ix., article "Hydrozoa," 1881. 



10. Weismann. Enstehung der Sexualzellen bei den Hydromedusen, 1883. 



Embryology : 



11. Balfour. Treatise on Comparative Embryology, 1880-81. 



12. Korschelt and Heider. Text-book of the Embryology of Invertebrates. Eng. 



trans., 1895-99. 



13. Metschnikoff. Embryologische Studien an Medusen, 1886. 



18 



