ORDER ANTHOMEDlS.i:. 19 



Family CODONIDjC Haeckel, 1879, sens, amend. 



Sarsiadat (in part), Founts, 1848, British Naked-eyed Medusa;, p. 55. 



Sarsiada+ Tubularidtf, McCRADY, 1857, Gymn. Charleston Harbor, p. 21. 



Sarsiadtf (in part)-t- Tubularidx+ Pennaridj: (in part), AGASSIZ, L., 1862, Cont. Nat. Hist. (-'. S., vol. 4, pp. ^9, 542. 



SarsiadtE+ Orthocorynidx + Tubulands + Pennanda, AGASSIZ, A., 1865, North Amer. Acalephx, pp. 175, 183, |S6, 189. 



Codonidz, HAECKEL, 1879, Syst. der Medusen, p. 9. VANHOFFEN, 1891, Zool. Anzeiger, Bd. 14^.442. HARGITT, 1904, Bull. 



Bureau of Fisheries U.S., vol. 24, p. 29. HARTLAL-B, 1907, Nordisches Plankton, Nr. 12, pp. 5, 6. 

 Codonina+ Cor\nid<z + Tubularidtt, VON LENDENFELD, 1884, Zool. Anzeiger, Bd. 7, pp. 446, 447. 



FAMILY CHARACTERS. 



Anthomedusae in which the gonad is ring-like and encircles the manubrium. Mouth with- 

 out oral tentacles or prominent lips. The 4 to 6 radial-canals are simple and unhranched. 

 \Yhen ocelli are present they are found upon the outer sides of the tentacle bulbs. There 

 are no marginal otocysts. The tentacles are neither branched nor feathered. 



Medusae of the genera Sarsia, Steenstrupia, Ectopleura, Pennaria, Amalthtfa, Trichorhiza, 

 Hyhocodon, H yJnc/ithys, Coryrutts, and Margt-lopsis are known to develop asexually through 

 alternation of generations from Tubulanan hydroids. Direct development of medusae from 

 the egg is unknown in this family, although medusae are budded asexually from the manubrium 

 of some species of Sarsia, from the basal bulbs of the tentacles of HybocoJon, and from those 

 of Sarsia. Actinula larvae are set free from the manubrium of Margelopsis and Hybocodon. 



Haeckel, 1879, considered the presence or absence of an apical projection upon the bell, 

 and the presence or absence of an axial canal extending upward from the stomach into this 

 apex, to be a criterion for the separation of genera. It should be borne in mind, however, 

 as was pointed out by VanhofFen, 1891 (Zool. Anzeiger, pp. 439-446), that the young medusae 

 often lack an apical projection and axial canal, whereas the mature individuals possess these 

 characters. They are also highly variable in development. We have therefore considered 

 these characters to be of specific but not generic value. 



A natural classification of the Codonidae can not be based upon the characters of the 

 medusae alone, for the medusae of Pcnnana and Amaltheea are similar, while their hydroids 

 are distinct, the former being Pcnnana and the latter Carymorpha, and an equally remarkable 

 condition is presented by hydroids belonging to the two genera Syncoryne and StaunJi/i, 

 both ot which give rise to medusae belonging to the genus Sarsia. This peculiar case is still 

 further complicated by the fact that at least one species of StauriJia hydroid gives rise to a 

 ClaJonema medusa. 



In HyJrichthys we meet with an extraordinary case of parasitism or commensalism of 

 the hydroid, and in Margelopsis we find a free-floating hydranth, recalling the hypothetical 

 ancestral form of the Siphonophorae. Margclnpsis is also interesting in that its medusae form, 

 apparently, a connecting link between the Codonidae and the Bougamvilleae, although they 

 are more closely related to the Codonidae than to the last-named family. Indeed their 

 resemblances to the Bougamvilleae are probably due to mere parallelism and not to blood- 

 relationship. 



The Codonidae may conveniently be divided into two subfamilies, as follows: 



(1) Srirsi/inn, with simple, unbranchtd, marginal tentacles, which arise singly from the bell-margin. 



One or all of the tentacles may he degenerate or absent. 



(2) Margelopstna, with marginal tentacles grouped into clusters. 



