PHYSALIA. 101 



3. Physalia utriculus. 



A long, fleshy, proboscidiform process at that end of the hydrosoma, which is 

 provided with appendages, distinguishes this species at first sight from tlie two preceding ; 

 the polypites arising singly from the hydrosoma, and the inequality of the tentacles, 

 among which one is very much larger than the other, are characters which it has in 

 common with P. pelaglca. 



In the largest specimens, the naked anterior end of the hydrosoma elongates into a 

 narrow, conical process, which is almost longer than the other part, provided with appendages. 

 At its extreme end, a small, fleshy, conical process of half a line in length is observable, 

 and is to be regarded as a part of the hydrosoma containing no air. In like manner, the 

 posterior end, beset on one side with short polypites, is not filled with air, but appears 

 as a narrow, fleshy, and thence moveable process, six lines long, which is continued by 

 two crura into the sides of the hydrosoma. Behind tlie middle there is observable 

 on the lower surface, a great, round, bluish spot, which arises from a flat, fleshy part 

 connected with the other thicker, fleshy streak. The long and not high crest commences six 

 lines behind the anterior end, and does not extend to the root of the posterior process. 

 PJiysalia utriculus attains a length of three and a half inches. As to its colour, the crest and 

 the middle part of the pneumatophore are greenish, the two extremities blue. It inhabits the 

 tropical regions of the Pacific. 



I must confess I feel anything but satisfied that these are really distinct species, but this 

 is a point which can only be settled by those who study these singular animals with modern 

 appliances and a knowledge of what has already been done. 



To such observers I would suggest that the number of primary and secondary septa in 

 the crest, and the exact mode of grouping of the appendages are more likely to yield 

 good distinctions than any other characters. 



Physalia utriculus ? {Esch.) PI. X; PI. XII, fig. K 



The Phi/salia which I examined appeared to me to belong to one species, whose 

 description I subjoin as I find it in my notes. 



The hydrosoma tapers to a point at one end, whence it gradually enlarges, and 

 becomes subcylindrical about the middle ; the otiier end is somewhat suddenly widened, 

 so that, viewed from above, the organ has, roughly speaking, a T shape. Along the middle 

 of the upper surface of the subcylindrical and pointed part of the hydrosoma, its 

 wall is raised up into a transversely plaited crest, which dies away on the enlarged end. 

 The rest of the upper surface and the greater part of the under surface of the pointed 

 and subcylindrical portions are quite smooth, and distended by the air contained in the 

 pneumatocyst. The under surface of the transversely enlarged end, on the other hand, is 

 very irregular, and gives attachment to the numerous appendages. 



