Diversions of a Naturalist

by Sir E. Ray Lankester

Fig. 2.—One of the polyps of Rhabdopleura which is attached by its soft contractile stalk (c) to the dark internal cord seen in Fig. 1. A similar polyp issues during life from the open end of each of the upright tubes seen in Fig. 1, and is, when disturbed, pulled back into the tube by the contraction of the cord c. a, mouth; b, vent; c, contractile stalk; d, head-shield or disk; e, the left gill-plane; f, the body-mass enclosing the intestine, etc. (From a drawing made by the author in Lervik, Stordö, in 1882.) For a full account of Rhabdopleura, see the "Quart. Journal of Microscopical Science," vol. xxiv., 1884.

We filled glass jars with sea water and placed the bits of coral in them, and I eagerly examined them for the creeper-like "Rhabdopleura." There, sure enough, it was on several of the dead stems of coral, and we sailed back to Lervik with our booty in order to examine it at leisure with the microscope whilst still fresh and living. In our temporary laboratory at the farmhouse the little polyp which it had been my chief object to study, issued slowly from its delicate tubes when placed in a shallow trough of sea-water beneath the microscope. I was able on that day, and many others subsequently—with renewed supplies from the depths of the fiord—to make coloured drawings of it, and to find out a great deal of interest to zoologists about its structure. The minute thing ([Fig. 2]) was spotted with orange and black like a leopard, and had a plume of tentacles on each side of its mouth, which was overhung by a mobile disk—the organ by means of which it creeps slowly out of its tube, and also by which the transparent rings which form the tube are secreted and added one by one to the tube's mouth, so as to increase its length. The creature within the tree-like branching system of tubes ([Fig. 1]) is also tree-like and branching, fifty or more polyp-like individuals terminating its branches and issuing each from one of the upstanding terminal branches of the tube system. I was able to determine the "law" of its budding and branching, and I also found the testis full of spermatozoa in several of the polyps, but I failed to find eggs. I believe that we were too late in the season for them; and they are still unknown.

One of the most interesting deep-sea creatures discovered by the "Challenger" proved to be closely allied to our little Rhabdopleura, and received the name "Cephalodiscus." Several species of this second kind have been discovered in the last twenty years in the deep sea, and the largest and most remarkable in some respects was one which "jumped to my eyes" among the booty of marine dredgings sent home from the Antarctic expedition of the "Discovery" by Captain Scott, when I unpacked the cases containing these marine treasures, in the basement of the Natural History Museum. I published a photograph of it in the "Proceedings of the Royal Society," and named it "Cephalodiscus nigrescens." But nothing more of importance has, as yet, been brought to light as to "Rhabdopleura."

Fig. 3.—A piece of the white branching coral (Lophohelia prolifera) dredged in great quantity by the author off Lervik in 1882. Drawn of the natural size.

Our rule at Lervik was to go out dredging from seven to twelve, and work at the material with microscope and pencil for some three or four hours after lunch. Of all the many beautiful things we dredged, the most striking were the various kinds of corals, the large, glass-like shrimps, the strange apple-green worm Hamingia (actually known previously by two specimens only), and the large, disc-like and branched, sand-covered or sausage-like Protozoa (from a shelly bottom of 200 fathoms depth). My friend Dr. Norman joined me at Lervik after I had been there for a month, and showed his extraordinary skill in choosing the most favourable spots for sinking the dredge and in pouncing on interesting specimens as we sorted the contents of the dredge (when we had been on a soft bottom) by passing them through the sieves, specially provided for naturalists' use, as we gently rocked on the dark surface of the clear, deep water, many miles from our island. The colours and light of that region are wonderful—the mountains of a yellow tint, far paler than the purple sea, whilst the rocky islands are fringed with seaweed of rich orange-brown colour, and clothed with grass and innumerable flowers.

The white coral of two kinds (Lophohelia and Amphihelia) is accompanied by beautiful purple and salmon-coloured softer kinds of coral (Alcyonarians), known as Primnoa, and by the gigantic Paragorgia. On one occasion our dredge became fast. For long nothing would move it, and we feared we should have to cut it and lose some 300 fathoms of rope. At last the efforts of four men at the oars set it free, and we wound it in. As the dredge came up we found entangled in the rope an enormous tree-like growth, as thick as a man's arm, seven feet long, and spreading out into branches, the whole of a pale vermilion colour (like pink lacquer)—a magnificent sight! It was a branch of the great tree-coral of these waters—the Paragorgia—and we preserved many pieces of it in alcohol and dried the rest. But the gorgeous colour could not be retained.

One day the green worm, Hamingia (named after a Norwegian hero—Haming) was dredged by us at the mouth of Lervik Harbour, in 40 fathoms. A somewhat similar worm lives in holes in the limestone rocks of the Mediterranean, and is named Bonellia (after the Italian naturalist, Bonelli). All the specimens of this Mediterranean worm, which is as large as a big walnut, and has a trunk, or proboscis, a foot long, were found to be females. The male was unknown until my friend the late Alexander Kowalewsky, the most remarkable of Russian zoologists, discovered that it is a tiny threadlike green creature, no bigger than the letter "i" on this page. Three or four are found crawling about on the body of the large female. I found the same diminutive kind of male crawling on my Norwegian Hamingia, at Lervik, and published a drawing and description of him. I was also able to show that, unlike Bonellia, the Norwegian worm has red blood-corpuscles, like those of a frog, and impregnated with hæmoglobin, the same oxygen-carrying substance which colours our own blood-corpuscles. The identity of the worm's hæmoglobin with that in our own blood was proved by its causing two dark bands of absorption in the solar spectrum when light was passed through it and then through the spectroscope—dark bands exactly the same in position and intensity as those caused by the red substance of my own blood and changing into one single band intermediate in position between the two—when deprived by an appropriate chemical of the oxygen loosely combined with it.

On the Fiord near Lervik.