1097 



CIRRIPEDIA. 



CIRRIPEDIA. 



(Lfpas anatifera of Linnaeus), the Common or Duck Barnacle. To the 

 references on this head in the article BERSICLE-GOOSE, we may add 

 the testimony of Sir Robert Moray to show how long the delusion 

 lasted, and in what positive terms a witness can state the thing that 

 is not. " In every shell that I opened I found a perfect sea-fowl ; the 

 little bill like that of a goose, the eyes marked, the head, neck, breast, 

 wings, tail, and feet formed, the feathers everywhere perfectly shaped, 

 and blackish-coloured, and the feet like those of other water-fowl, to 

 my best remembrance." So widely spread has been this delusion, that 

 it is stated that the Roman Catholics are permitted, in France at least, 

 to eat the Bernicle-Goose upon fast-days and during the whole of Lent, 

 in consequence of its supposed marine origin. 



Organisation, and place in the Natural System. Linnaeus placed 

 the t'irripcdia, with the generic name of Lepas, among the Multivalves 

 of his Vermes (Tegtacca), between Chiton and Photos; and, supposing 

 that the form existed without a shell, found a situation for it under 

 the name of Triton, between Terebella and Lerncea. Cuvier, in the 

 fir.st and also in the last edition of the ' Regne Animal,' says that the 

 existence of these Tritons is not confirmed, and that we must suppose 

 that Linnaeus had only seen the animal of an Anatifa (Penfalasmis), 

 which had been taken out of its shell. Rang, however, thinks that he 

 has found the Linnaean genus Triton in certain specimens brought 

 home by Messrs. Lesson and Garnot, Quoy and Gaimard, and has 

 published it under the name of A If pas. Bruguieres divided the genus 

 L pan into two ; the first, Anatifa, a barbarous word for Anatifera (the 

 Anatifes of the French), comprising the Pedunculated Cirripedes ; and 

 the second, Balanus, the Sessile species. Cuvier, under the name of 

 Cirrftopoda, made these animals the sixth class of his Mollusks, which 

 he places between the Brachiopoda and the first class (Ann<?lides) of 

 his third great division of the animal kingdom, namely, the Articu- 

 lated Animals, and in the ' Regne Animal ' they appear between 

 da, and Serpula. Lamarck, under the name of Cirrktpeda, his 

 tenth class of Invertebrate Animals, arranges them between the seden- 

 tary Annelida and his Conchifera, dividing them into two orders : 

 1st, the Sessile Cirripedes ; 2nd, the Pedunculated Cirripedes. In his 

 system they stand between Mayiliis and Asperyillum. Latreille, 

 though he does not disturb this ari-angement, evidently considers 

 them as related to the Ostracoda, among the Branchiopodous Crusta- 

 ceans. He says that the Sessile Cirripedes seem to represent the ani- 

 mals which terminate the Ace'phales Eufennc's of Cuvier. He observes 

 that the two tubular processes of Otion represent the two tubes of 

 gome of the Acephala, though with different uses, the tentacula being 

 converted into jaws. The cirri he considers as a kind of feet anala- 

 gcms to the sub-abdominal appendages of many Crustaceans, espe- 

 cially those of the Amphipoda, and is of opinion that we may also 

 compare them to those of many Annelides. The oviduct, he remarks, 

 has some resemblance to that of Phalangium. Finally, he expresses 

 a conjecture, that nature, to form the Cirripedes, has borrowed different 

 organs from animals of several classes. Mr. William Sharp M'Leay, 

 in his profound and philosophical work, ' Horse Entomologies:,' con- 

 that Pentalamit exhibits the greatest affinity with the Oilra- 

 coda; but he seems to be of opinion that there exists an affinity 

 between the shell of Jfalaniu and that of Echinus, and sanctions 

 Latreille's opinion that the articulated cirri have their analogues in 

 the arms of the Radiata, particularly of Comatula. Dr. Leach, who 

 has described several genera unnoticed till his time, divided the class 

 into two orders : 1st, Campylotomata, comprising the Pedunculated 

 section; and 2nd, Acamptummata, including the Sessile species. 

 M. de Blainville makes the Cirripedes the first class (Nematopoda) of 

 his ajib-type Malentozoaria, a group which corresponds to the Multi- 

 valvn.s of Linmeus, after separating from them the genus Pholaa, so 

 that De Blainville's Malentozoaria consist of the Cirripedes and 

 Chitons. The Cirripedes, he thinks, have an evident relation to the 

 Bivalve Mollusks, by means of their calcareous envelope, in which he 

 recognises the pieces of the shell of the Pholades, and even the ana- 

 logue of the tube of the neighbouring genera. He also considers the 

 relationship further indicated by the recurved position of the animal 

 fixed head downwards (la tete en bas) ; but he also considers that 

 their relations to certain animals of the type Eniomozoaria are nume- 

 l>y means of the horny, locomotive, articulated appendages 

 which are branchial, at least at the root, becoming, towards the mouth, 

 true horny denticulated jaws. Mr. Thompson, in his 'Zoological 

 Researches,' considers the Cirripedes to be true Crustacea, and that in 

 the first state of these animals they not only possess perfect freedom 

 .ind |>ower of motion, but organs of sight. On the 28th April 1823, 

 Mr. Thompson states that he took in a small muslin (owing-net while 

 crossing the ferry at Passage, among other minute creatures, a small 

 translucent animal, one-tenth of an inch long, of a somewhat elliptical 

 form, but very slightly compressed laterally, and of a brownish tint. 

 \\'hi!ii in a state of perfect repose it resembled a very minute mussel, 

 and lay upon one of its sides at the bottom of the vessel of sea-water 

 in which it was placed ; at this time all the members of the animal 

 were withdrawn within the shell, which appeared to be composed of 

 two valves, united by a hinge along the upper part of the back, and 

 capable of opening from one end to the other along the front, to give 

 occasional exit to the limbs. These were of two descriptions, namely, 

 anteriorly a large and very strong pair, provided with a cup-like 

 sucker and hooks, serving solely to attach the animal to rocks, stones, 



&c. ; and, posteriorly, six pairs of natatory members, so articulated as 

 to act in concert, and to give a very forcible stroke to the water, caus- 

 ing the animal, when swimming, to advance by a succession of bounds 

 after the same manner as the Water-Flea (Dapknia) and other Mon- 

 ocu.fi, but particularly Cyclops, whose swimming-feet are extremely 

 analogous. [BRANCHIOPODA.] The tail, usually bent up under the 

 belly, is extremely short, composed of two joints, and terminating in 

 four setae, and is employed to assist in progression and in changing 

 the position from a state of repose. The greatest peculiarity however 

 in the structure is in the eyes, which, although constantly shielded by 

 the valves of the shell, are pedunculated as in the Crab and Lobster, 

 and placed entirely at the sides of the body. Mr. Thompson observes 

 that this animal, but for its pair of peduuculated eyes, would find a 

 place as a new genus of Ostracoda; that its members approximate it 

 to Aryulus on the one hand and to Cyclops on the other genera 

 which are widely separated ; while the eyes show its relationship 

 to the Decapoda (crabs, lobsters, &c.) The individuals presented no 

 variation indicative of a difference of sex ; and this, with their anoma- 

 lous organisation, induced a belief that they were the larvae or dis- 

 guised states of some crustaceous animal, or (as it had been previously 

 ascertained that the Cirripedes were Crustacea) that they were the 

 males of these, Mr. Thompson not being disposed to believe that the 

 two sexes were united in the same individual. What follows being of 

 the last importance, we give in the author's own words : " Under 

 the foregoing impressions, some of them were collected in the spring 

 of 1826, and, in order to see what changes they might undergo, were 

 kept in a glass vessel, covered by such a depth of sea- water that they 

 could be examined at any time by means of a common magnifying- 

 glass; they were taken May 1st, and on the night of the 8th the 

 author had the satisfaction to find that two of them had thrown off 

 their exuvia (exuviae), and, wonderful to say, were firmly adhering to 

 the bottom of ,the vessel, and changed to young barnacles, such as are 

 usually seen intermixed with grown specimens on rocks and stones at 

 this season of the year. (Balanus pusilius, Penn.) In this stage the 

 sutures between the valves of the shell and of the operculum were visible, 

 and the movements of the arms of the animal within, although these 

 last were not yet completely developed ; the eyes also were still per- 

 ceptible, although the principal part of the colouring-matter appeared 

 to have been thrown off with the exuvium (exuviae). On the 10th 

 another individual was seen in the act of throwing off its shell, and 

 attaching itself as the others to the bottom of the glass. It only 

 remains to add, that as the secretion of the calcareous matter goes on 

 in the compartments destined for the valves of the shelly covering, 

 the eyes gradually disappear, from the increasing opacity thence pro- 

 duced, and the visual ray is extinguished for the remainder of the 

 animal's life ; the arms at the same time acquire their usual ciliated 

 appearance. Thus, then, an animal originally natatory and locomo- 

 tive, and provided with a distinct organ of sight, becomes permanently 

 and immoveably fixed, and its optical apparatus obliterated, and fnr- 

 'nishes not only a new and important physiological fact, but is the only 

 instance in nature of so extraordinary a metamorphosis." 



" During the whole of the spring and summer months," says Mr. 

 Thompson, ''the water teems with these exuvia (exuviae) of Triimnx 

 (the animal inhabitant, according to Linnaeus, of the barnacles) : it is 

 impossible to avoid drawing up numbers every time a towing-net is 

 thrown out, nay the tide is at times discoloured from their abundance ; 

 but to be certain that these are really such, let a stone with several 

 barnacles upon it be kept in sea-water, regularly renewed, towards the 

 latter end of April or the beginning of May. and with due attention 

 many of them may be observed in the act of throwing off exuvia 

 (exuviae) in every respect identical ; let it be recollected, however, 

 that these are the casts of the animal alone, and not of the valves of 

 the shell or of the operculum." Mr; G. B. Sowerby (' Genera of Shells,' 

 ' Scalpellum') thus writes on the subject of Mr. Thompson's disco- 

 very : " Without describing the facts, or entering upon the arguments 

 with which he supports this opinion " (that is, that the Cirripedia are 

 Crustacea), " we must be permitted to say that we do not think that 

 he has fully demonstrated it ; at the same time, considering that, as 

 far as we hitherto knew, the Cirripedes were all attached, the circum- 

 stance of their being free when very young accounts well to our mind 

 for the fact of each species being found attached to peculiar situations, 

 which would only be compatible with the notion of their being at one 

 time free agents, and possessed of an instinctive volition determining 

 their choice of situation." Professor Owen, in the ' Catalogue of the 

 Museum of the College of Surgeons' (' Cirripeda '), speaks of the dis- 

 covery without expressing any doubt. 



But Mr. Thompson has since, in a paper read before the Royal 

 Society on the 5th of March 1835, declared his " discovery of the 

 metamorphosis in the second type of the Cirripedes, namely, the 

 Lepades, completing the natural history of these singular animals, 

 and confirming their affinity with the Crustacea ; " and the Memoir, 

 with a plate, is published in the second part of the ' Philosophical 

 Transactions ' for 1 835. The following is the abstract of the paper : 

 " The discoveries made by the author of the remarkable metamor- 

 phoses which the animals composing the first family of the Cirripedes, 

 or Salani, undergo in the progress of their development, and which he 

 has published in the third number of his ' Zoological Researches," 

 ( p. 76), are in the present paper, which is intended as a prize essay for 



