818 Mii. J. lUTCiuE OX Hvjjuuius [Miiy 24, 



by its (Iwaifisli size — tlie diameter of the stem is only i, the length 

 of the hych'otlietw less than 4, their diameter .^ those of 

 typical Australian specimens (c/! table of dimensions given above). 

 Var. pKsilla is also to be distinguished by the slightly more 

 flaring margin of its hydrotheca-, and by its hyaline perisarc, for 

 that of the robust typical variety is tinged with brown. It is 

 possible that the discovery of their gonosomes may separate those 

 two forms si)ecifically. 



Pi'ofessor C Hartlaub, in his fine monograph of the genus 

 Serin,- arella (1900, p. 65), regards S. c)/lindrica, somewliat doubt- 

 f idly, as a synonym of S. integra AUman, described from New 

 Zealand specimens. The delicate texture of the liydrotliecte is so 

 difi'eient, however, from that of the ty\ie of Sertulardla which 

 bears intiathecal n arginal teeth, that, apart from other obvious 

 diflerences of foi-m, sculptuie, and proportion, I regard the 

 presence of inti-athecal teetii in Allman's species as sufficient, 

 in this case, to indicate specific difterence. 



Sertulakella polyzoxias Linna3us, 1758. 

 Var. coEXUTA Ritchie (?), 1909 J. 



A single fragmentary colony, 34 mm. high, repi^esents this 

 species. The hydrotheca? agree in structure with typical speci- 

 mens, bnt a single internode occasionally bears moi-e than one 

 hydrotheca. The habit of tiie colony, too, is much more definite 

 than that of the lax variety {(jracilis) of Biitish seas, for from a 

 definite, thick stem spring alternate biunches almost at right 

 angles. In this I'espect the specimen approaches A'ar. rohnsta 

 Kirchenpaner (1884, p. 38), from Cape of Good Hope, and var. 

 cornuta, from the neighbourhood of the Andaman Islands. The 

 absence of the gonosome precludes certain decision as to which 

 variety it belongs, but the trophosome agrees in detail with that 

 of var. cornrota. 

 Dimensions : — 



Stem, diameter 0'(i3-0'7() mm. 



llydrotlieca, length ot adnate portion . ()"32-0'45 mm. 

 ' ., „ free „ 0-28 0-39 mm. 



„ greatest diameter 0-24-0"25 nnn. 



„ diameter at mouth ()"17-0"18mm. 



Locality. St. 23, Five Islands, 8 to 12 t'atlK)nis, rock and Siind, 

 and mud ; rare. 



Sektulahella (^uAnianENs J>ale. 1884. (Plate LXXYJI. 

 figs. 12 «, 12 6.) 



The transverse chitinous jjrojections from the bases of the 

 liydrotheca' aie mostly absent, and where they do occur are much 

 less distinctly marked than in Bale's figui'e {\)\. \V\. fig. 5) of a 

 Holboin Island specimen. The hydrotheca^ are strictly alternate, 

 l)ut the intei'uodes are very irregular in length, fiom eleven 

 to thirty-six hydrothccie occurring lietween succe.ssive nodes. 



