O13ELIA GENICULATA. 119 



from which they had dropped. His inference was, that 

 the polypites and the coralline were distinct organisms, 

 and had no essential connexion with one another. 



1. O. GENICULATA, Linnseus. 



" KNOTTED-THREAD CORALLINE," Ellis, Corall. 22, pi. xii. b, B. 



SERTULARIA GENICULATA, Linn. Syst. 1312; Pallas, Elench. 117; Lamk. An. 



s. Vert. (2nd ed.) ii. 149. 

 LAOMEDEA GENICULATA, Lamx. Cor. flex. 208 ; Johnst. B. Z. 103, pi. xxv. figs. 



1, 2; Gossc, Devon. Coast, 84, pi. iv. (the free zooid). 

 CAMPAXULARIA GENICULATA, Flem. Brit. An. 548. 

 MONOPYXIS GENICULATA, Ehrenbcrg, Corall. roth. Meer. 73. 

 EUCOPE DIAPHANA, Agassis, N. H. U. S. iv. 322, pi. xxxiv. figs. 1-9*. 

 OBELIA GENICULATA, Allman, Ann. N. H. for May 1864. 

 EUCOPE ALTERNATA, A. Agassi?, North Am. Acaleph. 86. 



Plate XXV. fig. 1. 



STEM zigzag, sometimes sparingly branched, jointed at 

 each of the flexures, and thickened immediately below 

 them, so as to form a series of projections or rests, from 

 which the pedicels rise; HYDROTHEC^E somewhat ob- 

 conical, rather short, the length slightly exceeding the 

 width, with a plain margin, borne on short, annulated 

 stalks (rings 4-6), which are suberect and taper slightly 

 upwards ; GONOTHEO/E axillary, urn-shaped, attached by 

 a short ringed stalk (3-4 rings). 



GONOZOOID. UMBRELLA (at the time of liberation) very 

 shallow, discoid, colourless, presenting a reticulated ap- 

 pearance ; MARGINAL TENTACLES 24 ; SPOROSACS OVal. 



THIS species is distinguished from all its British congeners 

 by the peculiar structure of the stem. It is divided by 

 simple joints into a number of short and rather stout in- 



* The Thaumantias diaphana described by Agassiz in the Mem. Am. Acad. 

 iv. p. 300, is, according to A. Agassiz, the sexual zooid of another species, and 

 was wrongly referred by him to the present species in the ' Contributions to 

 the Nat, Hist, of the United States.' 



