[58] MR. JAMES RITCHIE OX HYDROIDS [May 28, 



cylinrli'ical gonangia with marked constriction tieneath the shallow 

 saucer-like top. 



From lo&ality c there are only a few hydrothec« growing upon 

 Sertularia distans. gonangia being absent. 



Localities, {a) Creeping on a polyzoon found on the bottom 

 of a lighter: St. Vincent, Cape Verde Islands; 30th July, 1904. 

 —(6) On a pebble, 10 fathoms : St. Vincent; 27th July, 1904.— 

 (c) Creeping on Sertularia distans : Porto Grande, shore-pools ; 

 ?Jnly, 1904. 



Campanularia mutabilis, sp. n. (Plate XXIII. figs. 3, 4, 5.) 



Rare .specimens occur creeping upon SertnUiria versliiysi and 

 Soleniopsis dendriformis. From a thick-walled, creeping, hydro- 

 rhizal tube the hydrothecfe arise at irregular intervals. They are 

 borne on thick-walled peduncles with a length roughly three- 

 fourths that of the hydrotheca, varying from 0-4 to 0'8 mm., 

 and marked by from four to eight well-defined twists. The hydro- 

 thecie are large but vary from Q-B to \-'2 mm. in length and fioin 

 about 0'5 to 0"6 mm. in breadth. They are almost campannlate 

 in shape, gradually widening upwards to the margin, which 

 is frequently oblique, is beautifully recurved, and is sometimes 

 reduplicated (PI. XXIII. fig. 3). A slight ridge of perisarc at the 

 base of the liydrotlieca forms a platform upon which a cujnosarcal 

 disc at the bottom of the hydranth rests, and beneath this, 

 seemingly within the peduncle, is a delicate basal septum. The 

 hydrothecfe are seldom set symmetrically upon their peduncles. 

 Owing to the state of preservation, the structure of the hydrantli 

 could not be recognised. The tentacles appeared to be few in 

 number. 



Gonosome not known. 



Localities, (a) St. Vincent, Cape Verde Lslands : gi-owing on 

 specimens obtained from the bottom of a lighter; 30th Jul\-, 

 1904.— (6) Piles of pier: Porto Praya; 12th Augu.st, 1904. 



The specimens fi'om Porto Praya (onlj^ a few hydrothecre have 

 been found) are considerably larger than those from St. Vincent, 

 but the specific structures in the two sets of specimens are 

 identical (cf. fig. 5 and figs. 3 & 4, PL XXIII.). 



Tills species approaches Lafoea pocillum Hincks 1868, from 

 which however it difiers greatly in shape and in possessing an 

 everted margin. From Campanularia corrugata Thornely 1904, 

 it may be distinguished by its strongly-twisted peduncle, its 

 campanulate shape, and its non-corrugated walls. 



Family S e r t u l a r 1 1 d .e. 

 Sertularia distans* Lamouroux 1816. 



A species lepresented by a few colonies growing upon a sea- 

 weed. The largast specimens are 7 mm. high, while the internodes 



• In accordance with the recent determination of Dr. A. Billard (1907), who has had 

 an opportunity of exaniinins: the type specimen of Lamouroux, I have suhstituted 

 the desiaiiation of that author for the more usual synonym S. ijryeilis Ilassall. 

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