216 BULLETIN 100, UNITED STATES NATIONAL MUSEUM 



The aperture is square, often several times reduplicated as in KitchieV 

 figure. Margin with four rather prominent teeth and operculum 

 with four flaps. 



Gonosome. — Gonangia fusiform, regularly and deeply annulated 

 with a quadrate collar from the corners of which four conspicuous 

 horns project horizontally as is well represented by Ritchie's figure. 



Localities. — Dredging station 5428, Eastern Palawan and vicinity, 

 30th of June Island, 9° 13' N., 118° 51' 15" E,; depth, 1.105 fathoms. 

 Station 5642, Buton Strait, Tikola Peninsula, 4° 31' 40" S., 122° 

 49' 42" E. ; depth, 37 fathoms. 



A comparison of this species with typical 8. polyzonias from Cape 

 Cod shows very material differences in the trophosome. The hydro- 

 thecae of polyzonias are fully twice as long as in cornuta and are 

 much more distant from each other. The colony of S. polyzonias is 

 branched in a very straggling and irregular manner instead of being 

 irregularly pinnate as in S. cornuta. The differences between the 

 gonangia have been noted by Eitchie. 



SERTULARELLA MIRABILIS Jaderholm 



Plate 42, figs. 3, 4 



Sertularella mirabiUs Jaderholm, Ueber Aussereuropaische Hydroiden des 

 Zoologisehen Museums der Universitat Upsala, 1896, p. 9, pi. 2. fig. 1. 



I have been unable to find any account of this truly remarkable 

 sertularian subsequent to the original description by Jaderholm and 

 feel that a description including that of the gonosome, which I 

 believe to be hitherto unknown, will be well worth while. 



Trophosome. — The colony is cylindrical in form, resembling a 

 sponge, 10 cm. high and l 1 /^ cm. in diameter. The main stem is 

 distinctly fascicled proximally for about 8 mm. It then breaks up 

 abruptly into a perfect maze of short slender profusely anastomosing 

 branches and branchlets which are indistinguishable from each other 

 and form a close network or web, a cylindrical mass of intricately 

 interwoven branches. The whole thing resembles in miniature what 

 is known as the " vegetable sponge " in tropical America. The 

 branching is so irregular as to defy description, there being ap- 

 parently no internodes and the branches often changing direction at 

 abrupt angles at which single hydrothecae often are found. Hydro- 

 thecae alternate as a usual thing and quite distant, although the 

 anastomoses are so frequent that there are seldom more than three 

 hydrothecae between forkings. Often the meshes inclose fairly 

 regular hexagons. Hydrothecae rather small, those in the fork- 

 ings having the form of truncated cones. The branchlets often 

 terminate in a hydrotheca which is hardly greater in diameter than 

 the branch that bears it as if on a pedicel. Lateral hydrothecae are 

 almost barrel-shaped, but larger below and plainly annulated 



