b "ENDEAVOUR SCIENTIFIC RESULTS. 



also has long internodes, with a pair of pinnae close to the top> 

 but the first few internodes bear no hydrothecae: the next two 



or three have usually a pair of hydrothecae in the middle, as in 

 8. patulum, and the rest have mostly two pairs instead of one. 

 8. mbventricosum has, like S. patulum, two or three short 

 internodes bearing hydrotheca? only, the rest being arranged like 

 the upper internodes of 8. orthogonium, with two pairs of 

 hydrothecae coming between every two pairs of pinna?. Here 

 however the nodes come between the two pairs of hydrotheca'. so 

 that an internode supports a pair of pinnae in the middle, with a 

 pair of hydrotheca? at the top and another pair at the bottom 

 (the two pairs therefore being pretty close together). There are 

 however in many cases less pronounced nodes just above the 

 pinna?, in addition to those described. Both in this species and 

 8. /Kitnl inn the joints between the proximal short internodes are 

 apt to be indistinct. 



How far these characters are to be relied upon is at present 

 impossible to determine, but many irregularities certainly occur ; 

 however the other characters will easily suffice to distinguish 

 8. subventricosum from either of the others. 



The gonangia are very small, about "75 mm. long and the same 

 in width, very little if at all compi"essed, and their markings are 

 of the same type as those of 8. elegans, but without the extreme 

 regularity indicated by Allman's figures. The alternating ridges 

 (which in all the specimens seen numbered five or six), are like 

 those of Sertularella divaricata and its allies, having a delicate 

 free-edged expansion or flounce running round them. 



It may be remarked in passing that the arrangement of the 

 stem-internodes described above will, if found to be sufficiently 

 constant supply a definite mark of distinction between 

 8. patulum and 8. Orthogonium, two species which in regard to 

 the form and arrangement of the hydrotheca? approach each 

 other closely. All my specimens of 8. patulum have the 

 proximal internodes short, without pinnae, while all those of 

 ,S'. orthogonium have them long, with pinna' only. The latter 

 arrangement is similar to that indicated by Marktanner- 

 Tuineretscher for his specimens of 8. campylocarpum, Allman. 

 Allman described that species as having no hydrotheca' on the 

 stem except an " occasional pair." Marktanuer-Turneretscher 

 says, however, that in his specimens the upper internodes bear 

 two pairs of hydrotheca? as well as a pair of pinna?, though the 

 lower ones bear pinna' only. I must admit my inability to find 

 anything to distinguish fif. campylocarpum from the earlier 

 S. orthogonium. Both Campenhansen and Marktanner-Turnerets- 

 cher say that the hydrotheca? of the specimens which they refer 

 to 8. campylocarpum are like those of 8. orthogonium, and 

 neither observer furnishes any reason for assigning them to the 



