123 



SCIENCE-GOSSIP. 



[June 1, 1865. 



and tlie earnest will to be converted into an in- 

 esbaustible source of amusement and instruction, — 



■Wliere you'd walk on eternal Tom Tidler's ground, 

 Picking up gold and silver. 



Over all, " the lark at heaven's gate sings," the 

 cuckoo utters its well-known note, the little birds 

 twitter in the boughs, the hawk suspends itself 'mid 

 air, and man alone, of all created things, is apt, in 

 getting or spending, to lay waste his powers, to 

 permit the literal El Dorado to absorb the ideal. 

 Where— 



He is gathering up a worldly store; 

 Though holding enough, he is longuig for more ; 

 And you'll meet him, despite his text profound, 

 Along with the crowd on Tom Tidler's ground, 

 Looking for gold and silver. 



THE KEYHOLE LIMPET AND ITS 

 PARASITE. 



By J. K. Lord, E.Z.S. 



THE Keyhole Limpet, I may briefly state for 

 the benefit of the unlearned in sheU-fish, is a 

 gasteropodous mollusc, belonging to the family 

 Fissurellidce, its generic name, fissurella, being 

 derived from the diminutive of fissura, a slit. In 

 shape and colour the shell closely resembles the 

 ordinary limpet {Patella vulgata), so common on 

 our British coasts ; possessing a like power of 

 adhering to the rocks, with a tenacity requiring 

 knife and hammer to overcome, — an obstinate ad- 

 herence, giving rise to a popular saying, " they stick 

 to you like a limpet to a rock" — its shape conical, 

 the base being occupied by a powerful muscle, which 

 is not confined entirely within the shell. It per- 

 forms the ofBce of leg^ by its expansion and con- 

 ti'action, ameans by .which the creature moves from 

 place to place on the rocks; a system of progression 

 you may see for yourselves if you watch a garden- 

 snail taking a constitutional over a cabbage. This 

 muscle also enables it to fix itself at pleasure, aided 

 by atmospheric pressure ]5 lbs. to the square inch. 

 They browse on sea-weed, and are usually found 

 between tide-marks. 

 At the apex of the shell is a hole, somewhat oval ; 



hence the name of Keyhole. This orifice is for the 

 escape of the outgoing branchial current. There are 

 about 120 species inhabiting all parts of the world, 

 India, China, Australia, and the Pacific at Vancouver 

 Island. When shell-collecting near Esquimalt 

 Harbour (Vancouver Island), I frequently picked 

 up empty fissureUas on the beach, but diligent re- 

 search at dead low water, in the rock pools, failed 

 to discover the living fish, neither did the di'edge 

 ever bring one up, from deep or shallow water. 

 The empty house, in this instance, was less de- 

 sirable than even a bad tenant, as the mansion 

 without its liege lord was a useless ruin. 



The tide at Vancouver Island plays aU sorts of 

 eccentric freaks, setting all tidal laws at defiance. 

 In May, June, and July, there is but one high and 

 one low water in twenty-four hours ; high water at 

 the change and full of the moon happening about 

 midnight. Springs range from 8 to 10 feet ; neaps 

 from 4 to 5. In winter there is a complete reversal 

 of this process ; but it will suffice for present pur- 

 poses to state that in summer the water is low 

 during the day, and in winter low during the night. 



Macauley's Point, a long ridge of slaty rocks 

 running far out to sea, but bare at low water, was 

 a favourite hunting-ground of mine, the snug little 

 rock basins generally afi'ording some novelty, left 

 prisoner by the receding water. An usually low 

 tide disclosed a ridge of rocks I had never before 

 seen — an opportunity for exploration not to be neg- 

 lected. Clinging to the slippery wrack, and sci'am- 

 bling down a vertical ledge, I discovered a regular 

 cave, its sides and floor literally covered with the 

 strangest collection of marine wonders I had ever 

 gazed on : — 



It was a garden still beyond all price 5 



E'en yet it was a place of jmradise. - 



« * K * 



Here, too, were living flowers. 

 Which, like a bud compacted, 

 Their purple cups contracted, 

 Now, in open blossom spread. 



Stretched, like green anthers, many a seeking head. 

 Others, like the broad banana growing, 

 Raised their long wrinkled leaves of purple hue. 

 Like streamers wide outflowing. — Ki:hama. 



Actinia spread their treacherous petal-like arms, 

 gorgeous in every variety of exquisite colouring ; 

 huge Holuthuria, like brilliantly-painted cucumbers, 

 clung to tiie dripping rock ; star-fish of all 

 sizes and tints — chitons in black spiny mail — 

 shells of purpura and trochus, and hosts of kindred* 

 Annelides too were peeping from out their cases of 

 stone and horn, their exquisite feathery tufts, fish- 

 ing-lines, and traps wondrously beautiful, but, like 

 the embrace of a siren, fatal in its clasp ;— all these, 

 hungry and anxious, waited for the coming tide. 

 Biding his time like the rest in this stronghold was 

 Sir Keyhole Limpet. 



