374 THE ZOOLOGIST. 



most interesting objects of study to the general zoologist, they 

 are at least not unimportant to man and his surroundings. 

 Minute Nematodes abound in moist soil around the roots of 

 plants, &c. In animal parasites we have the round worm, Ascaris 

 lumbricoides, which inhabits the alimentary canal of man; A. 

 mystax, found in the cat and dog, and A. megalocephala in the 

 horse and ox. Parasitic in plants, they cause the formation of 

 galls and other pathological growths; while the "Vinegar Eel," 

 Anguillula aceti, " which occurs so often in weak vinegar, is 

 another familiar example of this group." No fewer than "twenty- 

 two species have been described as parasitic in man," and hence 

 the cui bono which has often irritated so many amiable 

 naturalists can scarcely be applied with effect to the specialist 

 who investigates the life -histories of these unbidden guests. 



Rotifers are under the charge of Mr. Marcus Hartog. These 

 microscopic animals always recall to the mind of the writer that, 

 in conjunction with Hudson, his old correspondent, P. H. Gosse, 

 so aptly designated by Charles Kingsley as "that most pious and 

 most learned naturalist," passed the last years of a long zoologi- 

 cal vigil in their Monograph. Gosse was undoubtedly a true 

 zoologist, but there is a danger lest he be principally remembered 

 as the author of that bizarre publication ' Omphalos.' Mr. Hartog 

 bears witness to the value of the ' Monograph,' and may be said 

 to supplement it by giving the true biological details of the 

 group. It is surprising how many interesting details may be 

 studied in the life-histories of Rotifers. " Almost any organic 

 infusions freely exposed to the open air will yield Ploima shortly 

 after the active putrefaction is completed. The finer water weeds 

 yield most of the beautiful tubicolous forms. A whole group of 

 species and genera are quasi-pelagic in fresh and salt water, 

 constituting a large proportion of the ' plankton ' or floating life 

 near the surface ; and some of them are found in deep water, or 

 in the depths of the lakes." Others again are parasitic. 



Mr. W. Blaxland Benham has contributed a very useful 

 treatise on the Polychaet worms. Most marine anglers are 

 acquainted with that well-known and common bait the Lug- worm, 

 Arenicola marina, amongst other Polychaet lures, which form 

 part of the group of "marine worms, whose bodies are usually 

 elongated and cylindrical ; they either lead a free life swimming 



