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The only conclusion possible is that the observers do not see the same object, partly because the aurora is too low down and partly because there are optical illusions due to alignment. We are viewing a luminous sheet which is folded and refolded. We are also viewing a great collection of bright beams and bright pencils of light parallel to each other like the trees in a forest. Every slight change in the position of the observer alters the collective appearance of the pencils and the folds. The only method of determining parallaxes with any confidence consists in requiring two or more observers to start at the same point, fixing their attention upon one feature; separate to a short distance in opposite directions and return until they have satisfied themselves that the illusions due to perspective and alignment are not sufficient to nullify the influence of parallax.
Stated Meeting, January 21, 1898..
Present, 14 members.
Mr. Alden Sampson, a newly elected member, was presented to the Chair and took his seat.
Acknowledgments of election to membership were received from Richard Olney, William H. Dall, Leroy W. McCay.
Mr. Rosengarten read an obituary notice of the late Treas urer, J. Sergeant Price, Esq.
Dr. Hays was elected Librarian for the ensuing year. The appointment of the Standing Committees was referred to the President.
The following papers were presented :
For the Transactions:
Posthumous papers of the late Dr. Harrison Allen on
"The Glossophagina" and on
"The Skull and Teeth of the Ectophylla alba."
For the Proceedings:
"Specializations in the Lepidopterous Wing-PieriNymphalidae," by Mr. A. R. Grote.
"Description of Four New Species of Rocinela, with a Synopsis of the Genus," by Miss Harriet Richardson.
"An Old Broadside, with a Reference to the Throne of Congress," by Mr. Julius F. Sachse, which was discussed by Messrs. McKean, Rosengarten, Hildeburn and Sellers.
The meeting was adjourned by the presiding officer.
DESCRIPTION OF FOUR NEW SPECIES OF ROCINELA, WITH A SYNOPSIS OF THE GENUS.
BY HARRIET RICHARDSON.
(Read January 21, 1898.)
The species of Rocinela here described were collected by the steamer Albatross, of the U. S. Fish Commission, during its various cruises in different localities. One of the species herein described comes from the Alaskan coast; another is from the coast of Cuba, off Havana, and the third comes from the southern part of the Gulf of California.
The new species exhibit unique characters not found in any other representatives. One, R. cornuta, has the antero-lateral angles of the first thoracic segment extended forward on each side of the eyes, but not touching them, thus giving the head the appearance of being immersed or deeply set in this segment. Another, R. tuberculosa, presents a row of small tubercles on the posterior margin of each one of the thoracic and abdominal segments of the body. In R. cubensis, the frontal margin of the head is greatly produced into a large rounded process with a concave surface.
The genus Rocinela is now known to include nineteen species,' of which nine were included in the monograph published in 1880
1 R. lilljeborgii Bovallius (Bihang Sv. Ak. Handl., 1885, Vol. x, No. 10, pp. 3-10, Pls. I, 2) has been referred to the genus Syscenus Harger, and identified with S. inflexis, Harger's type species (G. O. Sars, "An Account of the Crustacea of Norway," Vol. ii, Isopoda, Pls. iii, iv, pp. 67, 68).
by Schicedte and Meinert,' and the others in the order hereinafter noted.
R. danmoniensis (pp. 383-389, Tab. xi, Fig. 1).
R. dumerilii (pp. 391–393, Tab. xii, Figs. 4–6).
R. aries (pp. 401-403, Tab. xiii, Figs. 7, 8).
"Description of Seventeen New Species of Crustacea," Lockington, Pro. Cal. Acad. of Sciences, 1876, Vol. vii, Pt. i, p. 46, 1877.
"On Some New Australian Marine Isopoda," W. A. Haswell, Proceedings of the Linnean Society of New South Wales, 1880, Vol. v, p. 472, Pl. 16, Fig. 2.
R. oculata. "Reports on the Results of Dredging, under the Supervision of Alexander Agassiz, on the East Coast of the United States, during the Summer of 1880, by the U. S. Coast Survey Steamer Blake, Commander J. R. Bartlett, U. S. N., Commanding," xxiii, "Report on the Isopoda," Oscar Harger, Bull. Mus. C. Z., 1883, Vol. ix, No. 4, pp. 97-99, Pl. 3, Fig 2. R. spongiocola. "Notes on Tasmanian Crustacea with Descriptions
of New Species," George M. Thomson, Papers and Proceedings of the Royal Society of Tasmania, 1892 (1893), pp. 57, 58, Pl. 3, Figs. 3-8.
R. laticauda. "Reports on the Dredging Operations off the West Coast of Central America to the Galapagos, to the West Coast of Mexico, and in the Gulf of California, in charge of Alexander Agassiz, carried on by the U. S. Fish Commission Steamer Albatross, during 1891, Lieut.-Commander Z. T. Tanner, U. S. N., Commanding," xxii, "The Isopoda," H. J. Hansen, Bull. Mus. C. Z., 1897, Vol. xxxi, No. 5, p. 108, Pl. 3, Figs. 2, 3.
R. modesta., op. cit., p. 109.
R. cornuta, sp. nov.
1 Symbolæ ad monographiam Cymothoarum, Crustaceorum, Isopodum, Familia," J. C. Schioedte et Fr. Meinert, Naturhistorisk Tidsskrift, 1879-1880, Vol. xii, pp. 383-403, Pls. 10-13.
R. cubensis, sp. nov.
R. japonica, sp. nov.
R. tuberculosa, sp. nov.
Analytic key of all the known species of Rocinela, with the addition of four new species.
a. Eyes contiguous.
b. Head produced into process in front. . . R. oculata Harger. b. Head not produced into process in front.
c. Flagellum of second pair of antennæ as long as peduncle.. R. spongiocola Thomson. d. Flagellum of second pair of antennæ more than twice as long as peduncle R. vigilans Haswell. a'. Eyes not contiguous.
b. Flagellum of second pair of antennæ with 14-16 joints. c. Eyes close together.
d. Head with frontal area excavated, bicarinated, front roundly produced with raised margin ...
R. danmoniensis Leach. d. Head without median excavation, not bicarinated . . . R. insularis Schicedte and Meinert.
d. Eyes widely separated.
d. Propodus of prehensile legs with two to four spines.
e. First thoracic segment with antero-lateral angles produced horn-like at sides of head. .
R. cornuta, sp. nov.
e. First thoracic segment normal.
g. Head not tuberculated.
h. Head with frontal excavation.
. R. cubensis, sp. nov.
i. Front bicarinated. . . . R. dumerilii Leach. i'. Front not bicarinated. R. japonica, sp. nov. h'. Head without frontal excavation
R. modesta Hansen.
f'. Frontal margin of head not produced.
h. Spots present on both sides of the fourth thoracic segment
R. maculata Schioedte and Meinert. h'. Spots wanting on fourth thoracic segment.
i. Spots present on fourth and fifth abdominal segment and base of terminal segment. . R. alaskensis (Lockington).
i. Spots wanting on fourth and fifth abdominal segments and terminal segment
R. americana Schiœdte and Meinert. g'. Terminal segment of body subtriangular; branches of uropods not crenulate on their exterior margins. R. orientalis Schioedte and Meinert. d'. Propodus of prehensile legs with five or six spines.
e. Increase in breadth of abdomen from base to fourth . . R. laticauda Hansen.
e. No increase in breadth of abdomen from base to fourth segment. R. australis Schioedte and Meinert. b. Flagellum of second pair of antennæ with ten or eleven joints. c. Tubercles developed on all the segments of the body. R. tuberculosa, sp. nov.
d. No tubercles developed on body.
Ega belliceps Stimpson (Proc. Ac. Nat. Sci., Philadelphia, 1864, xvi, p. 155), is also undoubtedly a Rocinela and may even prove to be identical with Rocinela alaskensis (Lockington) in which case the proper name will be Rocinela belliceps.
1Æga alaskensis Lockington (Proc. Cal. Academy of Sciences, 1876, Vol. vii, Pl. i, p. 46, 1877) must be referred to the genus Rocinela, as it agrees in every respect with the characteristics of that genus. When identifying Ega alaskensis Lockington with Rocinela, I found in conversation with Dr. Benedict that he had already recognized this relation.