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SAB (s) : Has a fairly small, bright, elongated nucleus crossed by a weak, twisted dark lane in the center of a weak and broad bar marking the major axis of a faint, diffuse and elongated lens with much spiral pattern of dark matter having a tendency to run parallel to the bar. Two main arms emerge near the extremities of the bar along a smooth, curved path turning sharply just outside the lens; their faint extremities tend to return to the lens along an almost circular outer loop, simulating an (R) structure in the early stages. Examples are NGC 1566 (illustrated from S 30"), NGC 5236 (M83), Sbc, NGC 4579, Sab and NGC 7392.

NGC 3718 55. NGC 3718 (W 60"): SAB (s) a. The bar is seen nearly ``end-on'' as in 51. Compare also with 30 and 54. Very peculiar-looking structures can be produced in the lens and nucleus of early SB (s) galaxies depending on tilt and orientation of the bar with respect to the line of sight.

SB (s) : This is the typical ``S-shaped'' barred spiral; it has a small, very bright and elongated nucleus distorted by a strong, twisted dark lane as it crosses over from one side to the other of the strong, narrow bar marking the major axis of a much elongated lens. Two strong, main arms start sharply at right angles to the bar at both ends and return faintly to it after completing a turn of a quasi-circular loop. Examples are NGC 1097, NGC 1300, NGC 1365 (illustrated from S 30"), NGC 5383. Later stages in this sequence are markedly asymmetrical as NGC 7479, Sc and NGC 7741, Scd (31). Some, like NGC 1300, have a third, fainter arm forming a half-ellipse close to the lens and indicating a transition toward the SB (rs) type.

NGC 7079 9. NGC 7079 (S 74"): SB (s) 0 o. Small bright nucleus in short and bright bar surrounded by very faint traces of spiral arcs in lens; extensive envelope. Compare with 12 and 13. NGC 1617 10. NGC 1617 (S 30"): SB (s) 0 +. Very small nucleus in short and fainter bar curving into spiral arms or arcs in lens and envelope. The spiral pattern is blurred by insufficient resolution here. Compare with 9 and 14.
NGC 1291 12. NGC 1291 (S 30"): (R) SB (s) 0 +. Fairly large nucleus on weak bar marking major axis of little elongated bright lens. Faint outer ring structure from which emerge two very weak spiral arms or arcs. No ring structure in lens. Compare with 9, 10 and 16. NGC 7552 29. NGC 7552 (S 74"): (R') SB (s) a. A small, elliptical nucleus in a bar-like, elongated lens with much internal structure marked by dark lanes; two main spiral arms (on stronger) emerge from the extremities of the bar and return each to the opposite extremity after a halfturn, thus simulating an outer ring structure. Compare with 10, 23, 30 and Plate X.
NGC 1365 30. NGC 1365 (S 30"): (R') SB (s) b. The upper right inset shows the complex structure of the nucleus due to the ``crossing-over'' of the main dark lane running along the bar which is seen here foreshortened in the projection; the two bright and knotty main spiral arms emerge at right angles to the bar and return to it after a half-turn (lower inset), thus simulating an outer ring. Compare with 27, 29, 31 and Plate X. NGC 7741 31. NGC 7741 (P 200"): SB (s) cd. The nucleus becomes inconspicuous in the bar (foreshortened in the projection); the two main, heavy arms show much branching and clumpiness; one is much stronger than the other, producing a characteristic asymmetry. Compare with 27, 30 and 32.
NGC 1313 32. NGC 1313 (S 74"): SB (s) d. Only a very small nucleus remains in the center of the bar from which emerge two short arms broken up into clumpy sections. The rest of the spiral pattern is weak, very irregular and strongly asymmetrical; note also the asymmetrical halfring on one side of bar. This is the transition stage towards the magellanic irregulars. Compare with 31, 36 and 37. SMC 36. Small Magellanic Cloud (AE 2"): SB (s) mp. The spiral pattern is reduced to the axial bar from which emerge one bright, knotty and asymmetrical arm (above, right) - including many supergiants - and one faint, smooth arm (lower left, invisible on print) including no bright supergiant. Traces of embryonic arms appear at the other extremities of the bar. The peculiarity is the asymmetrical distortion towards the Large Cloud (top right). Compare with 32 and 37.
NGC 55 47. NGC 55 (S 30"): SB (s) m (sp). The brighter part which is not resolved, except for a few bright emission knots and complex dark patches, represents a ``rear'' end-on view of the axial bar; the fainter part (left) which is partly resolved represents the end-on view of the main asymmetrical spiral arm. Between them dark clouds obscure the distant parts of the arm; weak embryonic arms can be identified to the right; compare with 36, 37, 38 and 48. NGC 4631 48. NGC 4631 (P 200"): SB (s) d or m (sp). The nearly central brighter part which is not resolved and against which complex dark clouds are projected represents a ``front'' end-on view of the axial bar; from it emerge two well-resolved, irregular spiral arms spreading out in opposite directions. Note characteristic asymmetry. Compare with 32, 38, 42 and 47.
NGC 7552 49. NGC 7552 (S 74"): (R') SB (s) a. Face-on view; same as 29; note outer loops. Details of bar and lens, seen from ``above'' are in 52; note pattern of dark matter. NGC 7582 50. NGC 7582 (S 74"): (R') SB (s) a. Broadside view; details of bar and lens, seen from ``across'', are in 53; note pattern of dark matter.
NGC 7552 52. NGC 7552. Detail of bar and lens. NGC 7582 53. NGC 7582. Detail of bar and lens.
NGC 5383 54. Lens of NGC 5383 (W 60"): SB (s) b. Seen nearly ``face-on'' as in 49; note structure of nucleus and pattern of dark matter; compare with 30.  

SB (rs) : has a fairly small, very bright and elongated nucleus crossed by a twisted dark lane, as in SB (s), in a very strong, very narrow bar marking the major axis of an elongated lens whose rim is brighter, especially near the extremities of the bar; this produces a characteristic ``dash-dot in brackets'' pattern, thus (- o -) from which emerge two main spiral arms with faint additional branches near the rim of the lens. Examples are NGC 4548, NGC 4593, NGC 7124 (illustrated from S 74"). Some, like NGC 4349, Sab, having a brighter lens and more continuous rim mark the transition toward SB (r).

NGC 5566 51. NGC 5566 (P 200"): SB (rs) a. End-on view; details of bar and lens, seen from ``along'', are in inset. There is an (r) structure in the lens which does not show up on this print. Note lane or layer of dark matter splitting outer arms.

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