NOTES ON PLYMOUTH HYDHOIDS. 147 



Clytea johnstuni, Alder. Medusie of this species were produced in 

 the aquaria in May. 



Obelia geniculata, Linn. Numbers of the medusre of this species 

 were bred in the tanks and bottles of the Laboratory during the latter 

 part of April. They may be readily distinguished from the medusa) of 

 Obelia dichotoma, which is very abundant at Plymouth, by the fact that 

 the former have 24 marginal tentacles, while the latter has but 16 at the 

 time of liberation. These small medusie are readily preserved with the 

 tentacles well expanded by stupefying with cocaine and passing through 

 three or four grades of alcohol. 



Obelia longissima, Pallas ? A specimen brought to the Laboratory 

 early in April is referred with some doubt to this species, which it 

 closely resembled in all respects, except in the fact that the hydrothecte 

 were marked with regular longitudinal flutings, the ridges between the 

 adjacent hollows terminating in blunt teeth at the margin. This beauti- 

 ful ornamentation was quite constant in the hydrothecte, and formed so 

 striking a feature as to suggest a new species. The close agreement, 

 however, of the specimen with Hincks' description and figures of 0. 

 longissima, taken together with the great delicacy of the hydrothecte of 

 the latter, render it probable that the form under consideration was 0. 

 longissima, with the delicate hydrothecaj shrunken so as to be thrown 

 into longitudinal flutings. The gonosome was not present. 



Secured in Millbay Channel from a depth of about eighteen fathoms. 



Campandlaria neglecta, Alder. This very minute Campanularian 

 was found growing on the stems of Tuhdaria indivisa. There were 

 several gonangia present, but the acrocysts were not developed. So far 

 as I can ascertain, C. neglecta has not been reported from Plymouth by 

 previous observers, probably having been overlooked on account of its 

 small size. It is only occasionally that the bimucronate ornamentation 

 of the margin can be made out. The stem in its manner of branching 

 and flexuose habit resembles a miniature G. Jlexuosa. 



Campanularia flexuosa, Hinchs. This beautiful species was found 

 with gonosome well developed, on May 1st. The gonangia differed 

 from Hincks' description in being ornamented with shallow but regular 

 annulations throughout their length. At first glance no indication of 

 this annulation is seen, but with proper treatment of light the markings 

 are plainly made out, and appear to be as symmetrical as those so 

 beautifully shown in the gonangia of Clytea Johnstoni. 



Campanularia fragilis, ffincks. Not before reported from Ply- 

 mouth. The single specimen secured from .the rocks near Millbay 

 Channel was destitute of gonosome, but showed the characteristic 

 tubular plain-rimmed hydrothecte of the species. The hydranths have 

 about twenty tentacles, and the proboscis is ovate in outline when 



