Protected by the abdomen of the Crab, or by the shell inhabited by the Pagurus, the parasite also no longer required the calcareous test, in which, no doubt, the first Cirripedes settling upon these Decapods rejoiced.
The supposition that certain Cirripedes might once upon a time have selected the soft ventral surface of a Crab, Porcellana or Pagurus, for its dwelling-place, has certainly nothing improbable about it.
They are almost the only Crustacea, except the Cirripedes already mentioned, which are normally hermaphrodite.
The remarkable larval metamorphoses ofCirripedes and the modifications of structure presented by some parasitic forms will be described in later chapters.
The nauplius larvae of Cirripedes are all more or less spiny, and the spines reach an exaggerated development in the larvae of the genus Lepas (Fig.
Of all Crustacean parasites, however, perhaps the most remarkable in their structure and life-history are the Cirripedes of the order Rhizocephala.
The only genus of Sessile Cirripedes agreeing with this in the number of principal valves is Catophragmus, Sow.
The Pedunculated Cirripedes are attached by a tubular tendinous process, called a peduncle.
The Linnaean name Lepas contains all the Cirripedes or Multivalves, the different kinds of which are not distinguished in the accounts given by early writers of the habits of the animals.
The remarkable shelly cups at the base of the pedicle is regarded as analogous to the shelly base of the Balanus, so that this genus would form an intermediate link between the Sessile and Pedunculated Cirripedes of Lamarck.
Balanus is the only genus of Sessile Cirripedes the shells of which consist of six parietal valves, except coronula, which has no shelly base, is flatter, and has the valves of the operculum placed horizontally.
A genus of Pedunculated Cirripedes without a shell.
This is the characteristic of the Sessile Cirripedes of Lamarck's system, the Balanidea of De Blainville.
The shells of the Sessile Cirripedes consist of two different sets of valves: 1st.
This family consists of the same animals which constitute the Pedunculated Cirripedes of Lamarck, and part of the genus Lepas in the system of Linnaeus.
The class Cirripedesof Lamarck constitutes the entire genus Lepas of Linnaeus.
The Complemental males of certaincirripedes live like epiphytic plants either on the female or hermaphrodite form, and are destitute of a mouth and prehensile limbs.
In this last and complete state, cirripedes may be considered as either more highly or more lowly organised than they were in the larval condition.
Hence we now positively know that sessile cirripedes existed during the secondary period; and these cirripedes might have been the progenitors of our many tertiary and existing species.
Cirripedes afford a good instance of this: even the illustrious Cuvier did not perceive that a barnacle was, as it certainly is, a crustacean; but a glance at the larva shows this to be the case in an unmistakeable manner.
These cirripedes have no branchiæ, the whole surface of the body and sack, including the small frena, serving for respiration.
Regarding the very remarkable means by which the basis of sessile Cirripedes is cemented to the surface of attachment, it will be convenient to defer for a little the description, on account of its necessary length.
In my former volume I have shown that the pedunculated cirripedes grow rapidly; this is likewise the case with the Balanidae.
Cirripedes are exclusively confined to these frigid zones, we may here disregard them.
In some sessile cirripedes a cleft, covered only by membrane, may be observed all round between the lower edge of the shell and the basis; a cleft of this nature is rather conspicuous in P.
From the fact of the pupa of other cirripedes having an abdomen, formed of three segments, placed exactly in the same position as the minute body here supporting the three pairs of spines, I believe this body to be the abdomen.
Sessile cirripedes adhere to all sorts of objects, floating and fixed, animal and vegetable, living and dead, organic and inorganic.
That Cirripedes have some special affinity to the Entomostraca, may be inferred from the fewness of the cephalic appendages, the biramous legs, the state of the abdomen, and the form of the carapace.
The duplicate type-specimens of my father's Cirripedes are in the Liverpool Free Public Museum, as I learn from the Rev.
That he was a thinker all along is true enough, and there is a vast deal in his writings previous to the Cirripedes that a trained naturalist could but emulate.
When on the coast of Chile, I found a most curious form, which burrowed into shells of Concholepas, and which differed so much from all other Cirripedes that I had to form a new sub-order for its sole reception.
The Cirripedes form a highly varying and difficult group of species to class; and my work was of considerable use to me, when I had to discuss in the Origin of Species the principles of a natural classification.
I am enabled to confirm and generalise these observations, in all the Cirripedes in the Order containing the Balanidae and Lepadidae.
I may here add, that the pedunculated Cirripedes never attain so large a bulk as the sessile; Lepas anatifera is sometimes sixteen inches in length, but of this, the far greater portion consists of the peduncle.
I may mention that I found sessile Cirripedes very sensitive of vibrations in objects adjoining them, though not, apparently, of noises in the air or water.
I was not able to perceive that this eye consisted of two eyes united, which the analogy of other Cirripedes makes me suppose probable, although in the ordinary and hermaphrodite Ibla quadrivalvis, the eye also appeared single.
It should be remembered that allCirripedes subsist on animals which happen to swim or float within reach of the cirri; but here it is only those which happen to crawl within reach of the probosciformed mouth.
Pedunculated cirripedes have two minute folds of skin, called by me the ovigerous frena, which serve, through the means of a sticky secretion, to retain the eggs until they are hatched within the sack.
Cirripedes afford a good instance of this: even the illustrious Cuvier did not perceive that a barnacle was a crustacean: but a glance at the larva shows this in an unmistakable manner.
These cirripedes have no branchiae, the whole surface of the body and of the sack, together with the small frena, serving for respiration.
These cirripedes have no branchiae, the whole surface of the body and sack, including the small frena, serving for respiration.
When on the coast of Chile, I found a most curious form, which burrowed into the shells of Concholepas, and which differed so much from all other Cirripedes that I had to form a new sub-order for its sole reception.
The Cirripedesform a highly varying and difficult group of species to class; and my work was of considerable use to me, when I had to discuss in the 'Origin of Species' the principles of a natural classification.
The above list will hopefully give you a few useful examples demonstrating the appropriate usage of "cirripedes" in a variety of sentences. We hope that you will now be able to make sentences using this word.
