HYDEOID ZOOPHYTES. 25 



It was found in our collection growing on other hydroids, such as Halecium 

 arhoreum, and also on algse and polyzoa. It is in some cases continued beyond its 

 support as a tangle of contorted tubes. 



Hydrosome. — Unbranched hydrocauli arise from the branching filiform hydrorhiza 

 at intervals to a height of 2" 5-10" mm. They are usually irregularly annulated 

 above and below, and there is always one well-marked convex annulus immediately 

 below the neck of the hydrotheca. According to Torrey this subthecal annulation 

 constitutes the only constant character of the species (24 : p. 51). 



The hydrotheca is bell-shaped and very constantly 1 mm. in length, but varies 

 considerably in diameter at the distal end (0'4-0"7 mm.) as well as in outline. The 

 margin is usually entire, but may be dentate. 



The material was not in a good state of preservation, but apparently the 

 hydranths have about 15 tentacles about 0*6 mm. in length. 



Gonosome. — The gonothecse are pear-shaped (I'O x 0*8 mm.) and supported by a 

 spirally marked pedicel rising from the hydrorhiza. The gonophores are apparently 

 female, but being badly preserved, details of their structure could not be made out. 



We have some hesitation in assigning these specimens to the species C. everta of 

 Clark, as they differ in many respects from the original description of the type. But 

 assuming that Mr. Torrey is correct in his statement that the species is very variable, 

 and comparing our specimens with his figures and description, the course we have 

 adopted appears to be a better one than that of founding for them a new specific name. 

 The specimens are clearly more closely related to C. everta than to C. Integra, or any 

 other species of the genus. 



Campanularia laevis. 

 (Plate IV., fig. 26.) 

 Campanularia laevis, Hartlaub, C, Zool. Jahrb., Supplement VI. (1905), p. 56-5. 



Localities.— ^ .Q., February 28th, 1902. McMurdo Bay ; - 20 fms. W.Q., 

 February 23rd, 1902. Flagon Point. 



Several colonies of this very beautiful hydroid were found creeping on the stems 

 of Halecium arboreum. The zooids are, with the exception of those of its supporting 

 species, the largest among the Calyptoblasts of the Expedition, and the large bell-shaped 

 hydrothecse with toothed margins — mounted on their straight but graceful pedicels — 

 are very striking. 



Hydrosome. — The creeping hydrorhiza gives rise at intervals to a number of 

 straight, upright, unbranched hydrocauli from 5 to 10 mm. in height. Each 

 hydrocaulus has two or three very obscure annulations at the base, and one clearly 

 marked convex annulation immediately below the hydrotheca. 



The hydrothecse are bell-shaped, slightly curved at the base, and then straight, 

 expanding gradually throughout their whole length. They are from 2 • 5-3 ■ mm. in 

 VOL. III. 2 F 



