The gigantic mollusk seen by Nemo

Horace Lunt, Across Lots, Boston, D. Lothrop, 1888, p. 179-181.

The crew of that wonderful sub-marine ship of Jules Verne’s imagination never encountered more surprising creatures than one can collect in a day’s search in any pond or stream within a radious of ten miles of the metropolis. The gigantic mollusk seen by Nemo at the bottom of the ocean would be less amazing to me than the larvae of the May-fly, the common caddis-worm, which have the curious instinct of building for themselves millions of homes for the protection of their dainty bodies against the crafty and greedy fish. There are several species, two of which we will at once put under our glass. They are working amid a thousand perils ; here a playful shiner swims up noiselessky to nibble, but the stone mason suddenly quits his labor and goes in. The danger being over, it cautiously shows its head again and resumes the occupation of clutching with its mandibles and feet small grains of sand, actually turning each grain over and over, as the workman in building a stone wall will turn a rock in his hands to decide its best fitting-place. Then with water-proof cement (saliva) it places grain after grain around the end the case until it is completed. In this little round stones house it crawl along on the bottom of the tank, comparatively safe, proving too much even for a fish’s curiosity, but at the expense of a very heavy burden, and, when in its native stream, eking out a most precarious existence of two species.
The other species under our observation is quite small and not so clumsy. Its house is made of short, narrow strips of grass, pasted together by the animal, and arranged in regular spirals. From it appear the head and two pairs of legs, by which it propels itself through the water, always maintaining a perpendicular position, and waltzing up to the surface in a most comical manner. We will rob this fellow of his home. The creatures offers some resistance, of course, but by careful maneuvering the burglary is commited without taking life. The interior is richly upholstered with fine spun silk, which no doubt secures the animal within the case, and prevents its tender body from rubbing too hard against the coarse material of which it is composed. On each side of the body are six pairs of leaf-like gills, connecting with air tubes by which this most interesting larva breathes. After viewing its forlon condition, we thrust it on the cold mercies of the aquarium, wherein it immediately sets about prospecting for another house.