282 " ENDEAVOUR " SCIENTIFIC RESULTS. 



(but this agrees with S. mediterranea), the base of the branches 

 is only slightly twisted, or not at all, and the annulation of 

 the gonotheca extends over a greater part of its length. 

 According to Billard the typical S. gandichaudi and 8. 

 mediterranea have the outer tooth of the hydrotheca longer 

 than the others, so that the aperture appears oblique ; this 

 character is present in our specimens to such a slight extent 

 as to be scarcely noticeable, and in many hydrothecae it is 

 not discernible at all. All these characters are of known 

 inconstancy, and the differences would not justify a specific 

 separation. The gonothecse may have either three or four 

 pointed teeth on the summit, and this in the same ' shoot. ^ 

 The type form, accordmg to Billard, has four, while the form 

 described by Allman as S. laxa is said to have three. It is 

 on Billard's authority that the latter is referred to 8. 

 gaiidichaudi . 



It is noticeable that in this species, although there are 

 four marginal teeth, the internal ones number only three, 

 and the same condition obtains in 8. microgona and 8. 

 angulosa, as well as in the species next to be described. 

 Hartlaub, it is true, describes 8. mediterranea as having 

 four internal teeth, but as he does not draw any distinction 

 in regard to this character between that species and the 

 internally toothed forms which he refers to 8. polyzonias, 

 it seems permissible to suspect that this is an oversight. 

 The Bass Strait specimen with internal teeth, which he 

 refers to «S'. polyzonias, is probably the same as the present 

 form. All my specimens are distinctly smaller throughout 

 than British examples of *S'. polyzonias. 



The distinction between 8. polyzonias and 8. gaudichaudi, 

 if finally upheld, will invalidate the record of the former 

 as a member of the Australian fauna. Its inclusion in 

 the " Catalogue of the Australian Hydroid Zoophytes " was 

 solely on the evidence of specimens with internal teeth 

 (though this feature was not observed till later), and I am 

 not aware of any other record of the occurrence of 8. poly- 

 zonias in Australia except Hartlaub's, referred to above. Up 

 to the present, therefore, the existence of the typical 8. 

 polyzonias has not been established, and it is quite probable 

 that many others of the locality -records which have con- 

 tributed to procure for it the character of ubiquity may 

 have also referred to forms such as that here classed as 8. 

 gaudichaudi. 



1. In a single shoot of S. polyzonias I find gonangia wdth three, four, 

 and five teeth. 



