HYDROZOA RITCHIE. 849 



darella cylindrica, var. pusilla. They show, moreover, that the 

 proportions of Syntheciutn alternans, AUman, (in whicli more 

 than half of the hydrotheca is adnate) differ very markedly from 

 those of ^. cylindricum.^^ Add to tliis the dissimilarity between 

 'tlie habits of these two species. S. alternans is, according to 

 AUman, *° "a strong., rather rigid form, with the stem fascicled 

 iiowards the base, ....... set witii piunatelv-di-posed, equi- 

 distant, alternate raniuli," which, in his figure are unbranched ; 

 while S. cylindriciim, is a somewhat lax form with unfascicled 

 stem, with branches which are irn.-gularly set, not equidistant, 

 iand not necessaril}^ alternate, and which are themselves some- 

 times branched. Consideration of these differences convinces me 

 that Billard {loc. cit.) has erred in regarding S. cylindricum as a 

 synonym of S. alternans. 



Localities. — Station 44, off Coogee, five to six miles from shore ; 

 depth, 49 to 50 fathoms; bottom, fine sand; i5th March, 1898; 

 •many colonies. Station 48, ofi" WoUongong, seven to eight miles 

 from shore ; depth, 55 to 56 fathoms ; bottom, sand and mud to 

 'rojk ; 18th March, 1898 ; few small colonies. 



In addition to the Port Jackson records of Bale, and those 

 -other Australian recoids given above, this species has been found 

 in San Diego Bay, California, whence it has been described by 

 Torrey as Sertularella halecina. 



SYNTHECIUM ORTHOGONIUM (Busk). 



■Sertularia orthogonia, Busk, Voy. " Rattlesnake," i., 1852, p. 390. 

 Id., Bale, Cat. Austr. Hydroid Zoophytes, 1884, p. 88, pi, 

 ix., fig. 11. 



.Synthecium orthogonia, Bale, Proc. Linn. Soc. N. S. Wales, (2), 

 iii., 1888, p. 767, pi. xvii., figs. 1-5. 



■ Synthecium orthogonium, Kirkpatrick, Sci. Proc. Roy. Dublin 

 Soc. (n.s.), vi., 1890, p. 604. Id., Billard, Ann. Sci. Nat., 

 Zool. (n.s.), xi., 1910, p. 25. 



Stations 10, 36, 54, and 57. 



Examples of this species come from four Stations, those from 

 Stations 36 and 54 being the more typical in appearance, and 

 resembling Bale's figure (1888, pi. xvii., fig. 1), while those from 



3 3 Gf. the above measurements with those of S. alternans type, given by 

 Billard— Ann. Sci. Nat., Zool., (n.s.), xi., 1910, p. 27. 



^0 Allman— Rep. Sci. Ees. -"Challenger," Zool., xxiii., 1888, Hydroida, 

 Pt. ii., p. 80. 



