Either to the simple lateral tail feathers with a few rami only, developed only on one side of the shaft and of uniform metallic coloration - or to the simple contour feathers of small size, with the usual symmetrical series of numerous rami right and left of the shaft and no remarkable colouring.
There is even a little treatise from the hand of Milton, published two years before his death, called Artis Logicae Plenior Institutio ad Petri Rami Methodum concinnata.
See Waddington-Kastus, De Petri Rami vita, scriptis, philosophia (Paris, 1848); Charles Desmaze, Petrus Ramus, professeur au College de France, sa vie, ses ecrits, sa mort (Paris, 1864); P. Lobstein, P. Ramus als Theolog (Strassburg, 1878); E.
A, malleate, with crop: this is followed enlarged view of malleus above - the by the crop-gizzard, Y-shaped incus consists of a short median also ciliated except fulcrum bearing two large rami, each of behind, where it is which is in contact with a stout malleus hardened into a set consisting of a toothed uncus carried on a of articulated sclerites long manubrium; b, sub-malleate, with (trophi) to form the enlarged view of malleus - the manubria gizzard or mastax.
Asplanchnopus myrmeleo, showing horseshoe-shaped germarium (left), blind saccate stomach (right), apical bladder, foot, &c.; g, Asplanchna ebbesbornii - the coiled tube at left is a kidney; h, i, incudate jaws of Asplanchna brightwellii and girodii chiefly formed of rami, with the rudimentary mallei parallel and external to them; j, Ascomorpha hyalina.
Complications follow upon this in other forms. Even in Mytilus and Arca a connexion is here and there formed between the ascending and descending rami of a filament by hollow extensible outgrowths called " interlamellar junctions " (il.
Posteriorly, at what is known as the root of the penis, the two corpora cavernosa diverge, become more and more fibrous in structure, and are attached on each side to the rami of the ischium, while the corpus spongiosum becomes more vascular and enlarges to form the bulb.
Thus, when acting as swimming organs, the appendages, or their rami, are more or less flattened, or oar-like, and often have the margins fringed with long plumose hairs.
When used for walking, one of the rami, usually the inner, is stout and cylindrical, terminating in a claw, and having the segments united by definite hinge-joints.
When specialized as bearers of sensory (olfactory or tactile) organs, the rami are generally elongated, many-jointed and flagelliform.
- A, Balanus (young), side rami are multiarticulate view with cirri protruded.
In the Isopoda the respiratory function has been taken over by the abdominal appendages, both rami or only the inner becoming thin or flattened.
The resemblances which the members of one class often present to the members of another class in regard to the form of the limb-branches (rami) of the parapodia, and the formation of tagmata (regions) are not hastily to be ascribed to common inheritance, but we must consider whether they are not due to homoplasy - that is, to the moulding of natural selection acting in the different classes upon fairly similar elements under like exigencies.
Such chelate rami or limbbranchesare independently developed in Crustacea and inArachnida, and are carried by somites of the body which do not correspond in position in the two groups.
The range of modification of which the rami or limb-branches of the limbs of Arthropoda are capable is very large, and in allied orders or even families or genera we often find d z what is certainly the palp of the same appendage (as determined by numerical position of the segments) - in one case antenniform, in another chelate, in another pediform, and in another reduced to a mere stump or absent altogether.
The principal forms assumed by the Arthropod parapodium and its rami may be thus enumerated: (1) Axial corm well developed, unsegmented or with two to four segments; lateral endites and exites (rami) numerous and of various lengths (certain 8 limbs of lower After Lankester, Q.
(4) Three of the rami of the primitive limb (endites 5 and 6, and exite I) specially developed as endopodite, exopodite, and epipodite - the first two often as firm and strongly chitinized, segmented, leg-like structures; the original axis or corm reduced to a basal piece, with or without a distinct gnathobase (endite i)- typical tri-ramose limb of higher Crustacea.
(6) Two rami developed (usually, but perhaps not always, the equivalents of the endopodite and exopodite) supported on the somewhat elongated corm (basal segment).
The rami may be flattened for swimming, when it is " a bi-ramose swimmeret," or both or only one may be filiform and finely annulate; this is the form often presented by the antennae of Crustacea, and rarely by prae-oral appendages in other Arthropods.
Its jointing (segmentation) may be retained, but its rami disappear (Podophthalmous Crustacea).
(2) Corm, with short unsegmented rami, forming a flattened foliaceous appendage, adapted to swimming and respiration (trunk-limbs of Phyllopods).
It may be pointed out that the most radical difference presented in this list is that between appendages consisting of the corm alone without rami (Onychophora) and those with more or less developed rami (the rest of the Arthropoda).
In the latter class we should distinguish three phases: (a) those with numerous and comparatively undeveloped rami; (b) those with three, or two highly developed rami, or with only one - the corm being reduced to the dimensions of a mere basal segment; (c) those reduced to a secondary simplicity (degeneration) by overwhelming development of one segment (e.g.
(b) Claws and fangs are developed on the branches or rami of the parapodia, not on the end of the axis or corm.
In all cases the appendages primarily develop rami or branches which form the limbs, the primitive axis or corm being reduced and of insignificant size.
In the more primitive forms the appendage of every post-oral somite has a gnathobase and two rami; in higher specialized forms the gnathobases may be atrophied in every appendage, even in the first post-oral.
These have small and insignificant rami, or none at all, a feature in which the Arachnida differ from them.
The mandibular somite bears a pair of gnathobasic hemignaths without rami or palps, and is followed by two jaw-bearing somites (maxillary and labial).
In fact, we have to suppose that the actual somite which in grades 1 and 2 bore the mandibles lost those mandibles, developed their rami as tactile organs, and came to occupy a position in front of the mouth, whilst its previous jaw-bearing function was taken up by the next somite in order, into which the oral aperture had passed.
The mandibular parapodia may be supposed during the successive stages of this history to have had, from the first, well-developed rami (one or two) of a palp-like form, so that the change required when the mouth passed away from them would merely consist in the suppression of the gnathobase.
On the whole the facts seem to be against this supposition, though we need not suppose that the gnathobase was very large or the rami undeveloped in the buccal parapodia which were destined to lose their mandibular features and pass in front of the mouth.