502 MR. JAMES RITCHIE ON HYDROIDS [May 28, 



are frequently marked by several " regeneration-lines," as in 

 specimens from the North Sea in my possession. 



The coppinia-gonosome is not present. 



Locality. Creeping on Soleniopsis deiidrifovniis, which was found 

 growing on the bottom of a lighter : St. Vincent, Cape Verde 

 Islands; 30th July, 1904. 



OuspiDELLA HUMiLis Hincks MS. & 1866. 



Minute hydrothecse arising here and there from a tubular 

 stolon creeping upon Soleniopsis dendriformis . The hydrothecse 

 are delicate and cylindrical, generally 0"2 mm. in height by about 

 0"05 in diameter, although a rare specimen attained a height of 

 0*4 mm. They show in many cases a tendency to contract 

 slightly towards the proximal end, while the distal end is crowned 

 by convergent opercular segments. They agree with Hincks's 

 description and figures of the species. 



Gonosome not known. 



Locality, {a) Creeping upon a polyzoon, which was obtained 

 growing on the bottom of a lighter : St. Vincent, Cape Verde 

 Islands; 20th July, 1904. — (6) Upon Soleniopsis dendriformis; 

 30th July, 1904. 



Family Campanulariid^. 

 Clytia geniculata Thornely 1904. 



Several small colonies, the largest rather under 1 cm. in height, 

 gi'owing on a polyzoon. The specimens agree in every respect 

 with the original description and figures, the peculiar method of 

 branching being particularly noticeable. The hydrothecse, which 

 are some 1"1 mm. long by 0*6 mm. in greatest diameter, bear 

 from 18 to 20 long teeth; each tooth being strengthened by a 

 median fold which is continued for a short distance down the 

 wall of the hydrotheca as a more or less definite line. 



The gonangia vary somewhat as regards their opening, some- 

 times having a plain, cylindrical, distal end ; at other times with 

 a distinctly constricted neck below the aperture. Sometimes they 

 arise in pairs from the base of a pedicel. 



Locality. Growing on polyzoa found on the bottom of a lighter ; 

 a single specimen on the back of a small crab. St. Vincent, 

 Cape Verde Islands; 30th July, 1904. 



Obelia dichotoma (Linnseus 1758). 



A few delicate colonies, the largest only 4 mm. high, occur on 

 the carapace of a minute ciub. The stems, which are unfascicled, 

 are divided by slanting nodes into regular intei'nodes 0*4 mm. in 

 length, from the distal end of each of which arises a hydrotheca. 

 Branches are frequent, sometimes 1*5 mm. in length, arising in 

 every case from the side of a pedicel. They are thus alternate, 

 and, like the stem, they bear alternate hydrothecse, from the 

 pedicels of which smaller branchlets with one hydrotheca may 



