[9] AN INDIRECT SOURCE OF THE FOOD OF FISHES. 763 



peculiar form of hypotrichons lufuBorian was detected, which was 

 clearly very nearly allied to Ghilodon cucullulus of Ehrenberg, but the 

 dorsal, non-ciliated side of its body was not gently rounded, but flat, 

 with a prominent crenate rim surrounding it. From this peculiarity it 

 may be called Ghilodon coronatus. 



The mode of swallowing their food adopted by the fresh-water Ehizo- 

 pods has been elaborately described in a few instances by Professor 

 Leidy in his splendid monograph of this group, published by the Geo- 

 logical Survey of the Territories. Their food appears to be mainly veg- 

 etable, and consists, for the most part, of diatoms and desmids, though 

 a ciliated Protozoan or Ehizopod was occasionally met with in the body 

 of Amceha. The marine Ehizopods appear to be herbivorous as well as 

 carnivorous, remains of both Protophytes and Protozoa having been 

 detected in their bodies. Vampyrella has been described as almost 

 parasitic upon the clustered frustules of GompJiotiema. 



Some aberrant ciliated forms, like the Gasfroiricha and Goleps, are 

 somewhat peculiar in their organization, and we know little of their 

 feeding habits. 



The Stictoria or Tentaculifera, which are abundant in some places, 

 both in fresh and salt water, appear to be indiscriminately herbivorous, 

 as well as carnivorous. In fresh water I have met with them infesting 

 the back of the common water leech, Glepsine, the species being appar- 

 ently Podoplirya quadripartita. Of marine forms I have seen but two 

 that I could regard as distinct from each other ; the one, a very common 

 form, is the old and well-known Acineta tuberosa of Ehrenberg, with two 

 clusters of suckers. This form I have frequently seen with diatoms 

 which it had seized and from which it was abstracting nutriment. The 

 other form was much larger than the preceding and appears to be iden- 

 tical with the species described under the name Podoplirya gemmipara 

 by Hertwig. It has the same robust stalk, with the same close trans- 

 verse annular markings, the same taper, and is similar in the form of 

 the tentacles, which are often irregularly bearded or swollen. I was 

 enabled to observe in part its development, which is also similar to that 

 of the Helgoland species of the North Sea, above mentioned. They 

 were found in great abundance on the surface of the fronds of Laminaria^ 

 together with the Acineta tuberosa ; not as abundantly, of course, as 

 the Zo'othamnium^ but in sufiftcieut numbers to make them a very con- 

 siderable factor in the protozoan life found in the vicinity of New Point 

 Comfort. 



The majority of the free Protozoa and many Monads, such as Xocti 

 li(ca, have scarcely been considered, but enough has been said, I think, 

 to give some idea of the actual importance of the minute animal and 

 vegetable life of the sea to make it clear that there is a most intimate 

 relation of dependence existing between the lowest and the interme- 

 diate forms of life. Why is it, for example, that we should find the 

 Copepoda so abundant among the Laminaria along the sea-coast ? Have 



