MOLLUSCA 303 



The Octopus (Octopus vulgaris) belongs to deeper water, and only small 

 specimens are found round our shores. It has much the same habits as the 

 Sepia, but does not discharge its ink so readily. Its principal food is small 

 crabs, lobsters, and similar marine creatures, for which it hunts after dark. 

 It has no internal " shell," (ike the Sepia, but two short rods of shelly matter 

 in the mantle. The body is like a round bag ; and the arms, eight in number, 

 with two rows of suckers on each, are connected at their base by a web. The 

 two eyes are fixed and staring. The arms of the Octopus are much longer than 

 those of the other Cuttle-fish, and by their means the animal not only seizes 

 and retains its prey, but is able to walk over smooth, perpendicular, and even 

 overhanging surfaces. There are some fifty species known to scientists, some 

 of which reach enormous sizes. Even the common species has been found with 

 arms 8 feet long, though fortunately specimens of that size do not inhabit British 

 waters, but other species have been found with bodies 8 or 9 feet long, and with 

 arms 30 feet long. 



As a rule it may be said that they are by nature timid animals, and 

 the romantic stories of their attacking human beings are the work of pure 

 imagination. 



The Squid (Loligo vulgaris) is another member of the Cuttle-fish tribe, 

 sometimes called the CALAMARY. It is longer and narrower than the Sepia, 

 which it resembles, having the same eight short arms (studded with only two 

 rows of suckers), and two longer tentacles. The mantle is also extended into 

 two short angular " fins " at the lower end of the body, which ends in a sharp 

 point. In place of the internal shell of the Sepia the Squid has a curious 

 horny pen, with a long shaft in front of it. 



It can both swim and crawl about head downwards. This species is 

 often used for bait, as also for human food. It is pinkish or yellowish white in 

 colour, with purplish brown spots, and is usually a foot or a foot and a half in 

 length. 



I have occasionally found the LITTLE CUTTLE (Sepia rondeletii) upon the 

 shore (for example, in Guernsey and Jersey). This is a very small species, 

 only some 2 inches in length, with rounded side-fins. It is easily identified. 



Snails and Slugs. These are land molluscs, though they have near relatives 

 both in fresh and salt water. Here, however, we deal entirely with those two 

 familiar slimy creatures which spoil our gardens. 



The largest and commonest species is the Garden Snail (Helix aspersa), 

 which hides in crevices of walls, heaps of stones, roots of plants, etc., and appears 

 to go back after feeding to the same hiding-place time after time. Its brown 

 shell with white tip is, unfortunately, well known to all garden lovers, and 

 shows the lines of growth referred to above very plainly. It should be noted 

 that the shell is in the form of a right-handed spiral, such shells being known 

 as " dextral." Some of our land snails (for example, Clausilia) have shells 

 which twist to the left, and are known as "sinistral." This applies to many 

 seashells as well. 



