PEOTOZOA OF HERTFOEDSniRE. 123 



Tlio first family, !Jronaflinfc, is tho simplest and perhaps lowliest 

 organized of all the Infusoria : the aniiiialeules are simply minute 

 specks of protoplasm of variable and unstable form moving about 

 by means of a single thread-like flagellum issuing from the anterior 

 extremity, and deriving their food by simple absorption of the in- 

 habited fluid. The characteristics of all the species are so uncertain 

 that I must refrain from further description ; they are to be found 

 everywhere, and are especially abundant in infusions of vegetable 

 matter. 



The animalcules belonging to the next family, Pleuromonadinse, 

 differ from tho foregoing only in being of a kidney shape, the 

 flagellum issuing from the concave side. 



In the third family, Cercomonadinoe, the animalcules develop at 

 will a thread-like extension of the body, serving as a pedicle. I 

 have found one representative of this family, Oikomonas mutabihs. 

 The animalcule is of a variable ovate form, and when attached by 

 its slender pedicle or footstalk, the flagellum is vibratile ; but when 

 swimming it is rigidly extended in front. This object was found 

 in an aquarium. 



The next family is Codonsecidae ; here the animalcules inhabit a 

 horny sheath or lorica. 



In the fifth family, Dendromonadinte, we find an advancement 

 in form; two flagella are developed, and the animalcules are 

 usually found in colonies, attached to tree-like branching pedicles. 

 In this family I have met with two highly-interesting examples. 

 The first, Bendromonm tirgaria, was found in a pond in Mangrove 

 Lane, attached to the leaves of Myriophyllum and growing most 

 luxuriantly in what appeared to be perfect forests of tiny crystal 

 trees. A more beautiful sight I have never seen. In this species 

 colonies of over a hundred zooids of a pear shape are attached to a 

 rigid hyaline pedicle, each zooid quivering by the action of the two 

 flagella which it possesses. 



The next example is Anthophysa vegetans ; here the animalcules 

 are pear-shaped, and attached in rosette-like mulberry-shaped 

 clusters of fifty or sixty zooids to the terminations of an irregular 

 branching pedicle (or zoodendrium, as it is often called), which is 

 of a dark brown colour and horny consistence, longitudinally 

 striated and stiff. In weakly specimens the pedicle is simply 

 granular and flexuous. This curious pedicle is the product of 

 excreted particles, from which the nutritive matter has been 

 extracted. Its substance has a close affinity to keratose, the horny 

 framework of sponges. 



I found a specimen a short time ago containing eight clusters of 

 monads, and I noticed that the pedicle at the point of junction with 

 the cluster was sufficiently soft and flexible to allow of a partial 

 gyration backwards and forwards, caused by the vibrations of the 

 inmimerable flagella. By following up Mr. Kent's investigations 

 I was able to see the exact manner in which this pedicle was built 

 up. I fed the group with very fine carmine, the particles of which 

 were greedily incepted; each monad was soon gorged with the 



