Home / Albums / Natural History / Shellfish 26
- Fiddler-Crabs
Among our first acquaintances of the sea-shore are sure to be a number of merry little sprites which do not seem to have yet mastered the lesson of walking straight ahead. Their movements will be seen to be in a direction at right angles to that towards which the head points. It is a very interesting sight to watch these apparently one-sided creatures hurrying off in their lateral progression towards their burrows in the sand or mud, or in quest of food. Pass them, and you will be surprised to see how quickly some of them will reverse their motion, seemingly without so much as pausing to glance at their pursuer, their machinery appearing to have given out at one end, thus compelling them to reverse and travel back over their old courses. - Warty Hermit-Crabs
Differing widely in structure and habits from the Calling-crabs, and affecting watery situations near the shore, are to be found the Hermit-crabs. These sprightly little animals, which are usually of small size, and have truly habits of their own, that stamp them at once as being original and distinctive, are a source of never-failing delight to the student of nature. They derive their name, as is well known, from the seclusion into which they cast themselves as the inhabitants of the shells of other animals, but it is probably not generally known, however, that the rights of tenantry are oftentimes exercised in the most arbitrary manner. Not always satisfied with a dead shell, the Hermit-crab has been seen to raid upon a living possessor and attempt to drag him from his home, in which operation the assailant is often assisted by a number of his fellows, each bearing with him his castle as defensive armor. True, the attack is probably made in many instances for the purpose of getting possession of the enemy as well as his belongings, and, however this may be, forcible possession is by them considered no misdemeanor. - Nautilus
A section through the Pearly Nautilus, Nautilus pompilius, common from Malay to Fiji. The shell is often about 9 inches long. The animal lives in the last chamber only, but a tube (S) runs through the empty chambers, perforating the partitions (SE). The bulk of the animal is marked VM; the eye is shown at E; a hood is marked H; round the mouth there are numerous lobes (L) bearing protrusible tentacles, some of which are shown. When the animal is swimming near the surface the tentacles radiate out in all directions, and it has been described as "a shell with something like a cauliflower sticking out of it." The Pearly Nautilus is a good example of a conservative type, for it began in the Triassic Era. But the family of Nautiloids to which it belongs illustrates very vividly what is meant by a dwindling race. The Nautiloids began in the Cambrian, reached their golden age in the Silurian, and began to decline markedly in the Carboniferous. There are 2,500 extinct or fossil species of Nautiloids, and only 4 living to-day. - Pearly Natilus
- Pterocera scorpio
The Squill seems to form a connecting link between the last and present order. It is the only genus of the heterobranchial Crustacea in which [Pg 138]the eyes are placed on footstalks; the head, instead of being distinct, appears in a great measure drawn into the corslet. It has been called the Sea Mantis, from its bearing some resemblance to an insect of that name, on account of the singularly-formed hooks with which two of its foot-jaws are armed - Unio Batava
- Land Crab
- Leodice sanguinea
- Limulus cancriformis
- Mysis chamæleon
- Nocolusia Banksii
- Polyphemus gigas
- Squilla maculata
- THE ZOEA OF THE COMMON CRAB
- Argonaut
- Chiton squamosus
- Cockle
- Cuttlefish
- Harpa musica.
Harpa musica. - Oliva porphyria
- Hermit Crab
- Anatifa lævis
- Arenicola piscatorium
- Cyclops minutu
- Cyclops quadricornis
“The body of this creature is covered with crustaceous or shelly plates, which overlap each other, and admit both of a lateral and vertical motion between them. Their ends do not meet on the side, but have sufficient space between them for the insertion and play of the organs of respiration. The rostrum, or beak, is short and pointed: it is a prolongation of the first segment which forms the head. A little above the beak, a single eye is imbedded beneath the shell, of a dark crimson colour, nearly approaching to blackness. The true form of this organ it is difficult to determine. Mr. Baker gives it the shape of two kidney-beans placed parallel to each other, and united at their lowest extremities. When viewed laterally, it appears round, while in some other positions it is square.” The eggs are curiously placed in two bags, presenting an appearance similar to clusters of grapes, and of considerable magnitude, compared with the size of the animal. These egg-bags are seen in the engraving, (which represents a female,) projecting from each side of the hinder portion of the shell. The centre of each egg is of a deep opaque colour, which in some specimens is green, in others red. The young of the Cyclops, when first excluded from the egg, are extremely minute, and so different from the mother, that Müller has described them as forming two distinct genera. - Halithæa aculeata