(From the New York News, April 5th.)
The Fenians Abroad.

Startling Statements from the O’Mahony Headquarters— An Expedition from New York at Sea— Another Expedition from California— Destination of Both Bermuda— Alleged Departure of Three Armed Vessels and About Six Thousand Men Probably from the Port of New York— The Plan of Future Operations.

No little whisper has been created in Fenian circles by the sudden departure of B. Doran Killian from this city [New York] on Monday last, and all day yesterday and on Tuesday vague reports were afloat that something extraordinary was on the carpet.

The fact seems to be that our correspondent’s authentic account of the escape of Stephens from Ireland, added to the consequent paralyzation of the sale of the Fenian bonds, had necessitated the immediate inauguration of some movement in order to sustain the waning enthusiasm of the Fenian Brotherhood and prevent their going over to the Sweeney plan of commencing hostilities with an invasion of Canada. Whether this be or be not true, an impatient demand seems to have been informally preferred that something be done and done immediately. On the other hand, it is claimed by those well learned in the secrets of Fenianism, that the expedition has been on the carpet for some time, and that every preparation has been made to render the expedition a success. Subjoined will be found as full a collection of the facts connected with the affair. if Fenian sources of information my be considered unquestionable. The account below has been collated by our reporter from the most accessible Fenian sources, and nothing is set down except what is sustained by the asseverations of Fenians of high office in connection with the movement. The details are somewhat meagre, but are sufficient to give an idea of the strength of the alleged.

FENIAN EXPEDITION ON FOOT.
The authorized statement from the O’Mahoney headquarters is to the effect that B. Dora Killian, Whilom Secretary of the Treasury F. B. started on Monday evening in company with an expedition consisting of three steamers— two propellers and one sidewheel steamer of fast sailing qualities unrivaled. The expedition was fitted out with 3,000 men well officer both officers and men being mostly composed of veteran sailors who have fought during the late war with the South. These vessels are well armed and equipped, one of them being a formidable iron clad carrying two one-hundred pound Parrott guns— one for and one aft—- and four rifled guns of the heaviest calibre amid ships. Large quantities of ammunition and spare arms have been put on board, all intended to find their ultimate destination in Ireland.

The second part of the expedition is composed of a couple of propellers, capable of making eighteen miles per hour under a full herd of steam. These vessels are also fully armed and equipped and have on board a complement of 2,730 men, besides those necessary to manage the vessels. These men have all been selected from the skilled veterans of the late war with the South, and are fully armed and equipped for service in the field.

[The whole number accompanying the expedition, exclusive of sailors, is, therefore, according to statement, 5,730 Reporter.]

These vessels are said to be fitted out with a view to the severest naval combat, if rendered necessary by any contingency, and are thought to be equal to any emergency which, with the exercise of due caution, can possibly occur.

Both expeditions are in the hands of eminent Fenians, and are commanded by experienced naval officers, who have seen service during the war. Captain Downing being in command of the second expedition, and the whole three vessels are manned with picked men. B. Doran Killian is invested with the supervision of both expeditions.

It is also asserted at headquarters that seven war-ships have left the coast of California, simultaneously with the above named from an Eastern port a given telegraphic signal having been agreed upon which would prevent the possibility of any failure of the California expedition to sail upon receipt of the telegram that all was ready in New York. These California vessels are said to be models of the naval fortress, and are armed and equipped in a manner vieing with the armaments of the Eastern portion of the expedition. The California expedition takes out in round numbers 10,000 men fully armed and equipped for field service.

Other expeditions have, it is stated upon competent authority, left several Northern ports simultaneously with the above– all armed with every implement of naval and land service, and commanded by men of ability and experience.

THE PLAN OF OPERATIONS.
The plan is understood to be to seize Bermuda, and make it a base of supplies, after which with as little delay as possible, the whole expidition will be put to sea, falling upon British commerce, and sweeping British trade from the seas with the bosom of destruction, and enacting over again the careers of the Alabamas, the Shenandoahs and the Petrels of the Confederacy.

Other expeditions will follow at as early a date as possible. These will be designed to operate directly upon the Irish coast, where, at a given point, a landing will be effected.

THERE WHEREABOUTS OF JAS. STEPHENS.
It is also claimed in Fenian circles that Stephens will be in Ireland before long before the landing of the expedition, his present whereabouts being a certain point on the coast of France, within easy distance of Ireland. The fitting out of the expeditions mentioned above has been by his order, and the entire plan has been conceived and managed by his authority.

The Irish people are to be ready at a given signal to fly to arms in every part of the country— that signal being the lighting of fires upon the hilltops on the island, and to prevent mistakes, the exploding of rockets burning with a certain specified combination of colors, which have been agreed upon. It is believed that 300,000 men, variously armed, can be gathered about the banners of the I. R. B. in Ireland, and these, with 25,000 veterans, are believed to be sufficient to expel the English forces, which consist of 37,000 regular troops and about 9,000 constabulary, and of which Stephens claims at least one-third to be Fenians.