146 Mr. E. Forbes on two Species of Cydippe. 



were longer (especially when first caught), melon-shaped and 

 not so broad as long. Sometimes they appeared a little longer 

 than at others, but they never altered their forms in the man- 

 ner reported of Bero'e cucumis by Fabricius and by Dr. Ma- 

 cartney » The body of both is divided into eight longitudinal 

 lobes, the furrows separating, which are deepest in the first 

 species ; on the summit of each lobe is a cihferous ridge, not 

 however continuous from mouth to anus in either case. The 

 cilia when in motion are beautifully iridescent. The second 

 species generally exceeds the first in size, and is slightly more 

 elongated, but is comparatively a sluggish animal. The cilia 

 of the first are very large compared with those of the second, 

 and consequently the first species is much more hvely in its 

 motions. It is also a much less delicate animal, bearing 

 transportation with comparatively little injury. 



It swims by striking the rows of cilia exactly as a fish strikes- 

 the water with its pectoral fins : sometimes it moves them 

 slowly, sometimes extremely quick, sometimes when in mo- 

 tion, and sometimes when at rest. At times the animal 

 seems quite quiescent, but the least motion in the water ex- 

 cites it to move its cilia. It always strikes the cilia towards 

 the anal extremity, and in no instance did either .species swim 

 with that extremity forwards. At the anterior end of the ani- 

 mal is the mouth, which contracts and dilates irregularly, and 

 occasionally pouts out, when it appears lobed. The mouth 

 opens into a cavity or stomach, slightly contracted superiorly, 

 and extending more than half-way into the centre of the ani- 

 mal. This stomach contracts and dilates also irregularly and 

 is lobed. When contracted, the folds appear as if coloured 

 (purplish), and are apt to mislead the observer into the notion 

 that they are separate organs or vessels in the stomach, which 

 however when dilated presents no trace of them. Near the 

 base of the stomach is a translucent brownish tongue-shaped 

 organ of some size, the nature of which I cannot guess. It 

 has the power of changing form, sometimes lengthening and 

 at other times contracting. It does not extend altogether to 

 the base, but appears to terminate in four hooked-shaped pro- 

 cesses, which are lodged in what seems the bilobed extremity 

 of the stomach. From the end of the stomach there is a very 



