504 MR. JAMES RITCHIE ON HYDROIDS [May 28, 



cylindrical gonangia with inai'ked constriction beneath the shallow 

 saucer-like top. 



From locality c there are only a few hydrothecee gi^owing upon 

 tSertularia 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. 

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

 (c) Creeping on Sertidaria distans : Porto Grande, shoi-e-pools ; 

 ? July, 1904. 



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



Rare specimens occur creeping upon Sertidaria versluysi and 

 Soleniopsis dendriformis. From a thick- w^alled, creejDing, hydro- 

 rhizal tube the hydrothecpe 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- 

 thecse are large but vary from 0'8 to 1*2 mm. in length and from 

 about 0"5 to 0'6 mm. in breadth. They are almost camj)anulate 

 in shape, gradually widening u]3wards to the mai-gin, which 

 is frequently oblique, is beautifully recurved, and is sometimes 

 reduplicated (PI. XXIII. fig. 3). A slight ridge of perisai-c at the 

 base of the hydrotheca forms a platform uj)on which a ccenosarcal 

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

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

 hydrothecse are seldom set symmetrically upon their peduncles. 

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

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

 niimber. 



Gonosome not known. 



Localities. («) St. Vincent, Cape Verde Islands : gi'owing on 

 specimens obtained from the bottom of a lighter ; 30th Jul}', 

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



The specimens from Porto ~PrajSb (only a few hydrothecag 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, PI. XXIII.). 



This species approaches Lafoea pocillum Hincks 1868, from 

 which howeA^er it differs 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 Sertulariid^. 



Sertularia distans* Lamouroux 1816. 



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

 weed. The largest 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 examining the type specimen of Lamouroux, I have substituted 

 the designation of that author for the more usual synonym -S. gracilis Hassall. 



