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\section{Analysis of New Bones}  BC\_18.88-0.09 ("the black mamba") is our strongest bone, in that it is highly elongated (0.8 degrees or 52 pc) and \textit{exactly} along a previously-claimed spiral arm trace in p-p-v space, although its orientation makes it less elongated than Nessie on the sky. In figure \ref{fig:Candid5_pos_vel} we show a p-v diagram in the longitude range of filament 5 BC\_18.88-0.09  and overlay the \citet{Dame_2011} global log-fit to CO for the Scutum-Centaurus arm. We see that the HOPS, BGPS, and GRS-determined velocities associated with filament 5 are highly correlated with this global-log fit, suggesting that filament 5 BC\_18.88-0.09  is marking a "spine" of the Scutum-Centaurus arm in this longitude range. Moreover, filament 5 BC\_18.88-0.09  also lies along a CO peak in longitude-latitude space, as evident in figure \ref{fig:Candid5_pos_pos}. By overlaying a trace of the mid-IR extinction feature of filament 5 on a plane of the sky map (integrated in Scutum-Centaurus's velocity range in the region around filament 5) we see that filament 5 BC\_18.88-0.09  lies in the center of the most intense CO emission. Finally, figure \ref{fig:Candid5_with_tilt} shows that filament 5 BC\_18.88-0.09  lies within $\approx$ 10 pc of the true physical mid-plane. All these figures taken together indicate that filament 5 BC\_18.88-0.09  is Nessie's counterpart in the first quadrant, suggesting that Nessie is not a curiosity, but one of several bones that trace significant spiral features. Our study is not the first to look for long filaments associated with spiral structure. \citet{Ragan_2014} and Wang et al. (2015) have undertaken similar studies. However, ours is the first study to \textit{specifically look for bones in regions we are most likely to find them, that is, elongated along the galactic plane}. They identify these filaments using three criteria: morphology, temperature, and velocity coherence.   In the former study, \citet{Ragan_2014} undertook a blind search (not restricted to latitudes where the mid-plane should lie) for long thin filaments in the first quadrant of the Milky Way, using near and mid-infrared images. In addition to confirming that Nessie lies along the Scutum arm, \citet{Ragan_2014} find seven GMFs, of which only one, GMF 20.0-17.9, is said to be associated with Galactic structure (declared a spur of the Scutum-Centaurus arm). Our strongest bone candidate, filament 5, BC\_18.88-0.09,  is a subsection of GMF 20.0-17.9, but, unlike \citet{Ragan_2014}, we argue that filament 5 BC\_18.88-0.09  runs right down the spine of the Scutum-Centaurus arm in p-v space. We believe the discrepancy arises due to a difference in methodology. \citet{Ragan_2014} group neighboring IRDCs into a single filament, while we determine that there is a significant kink in velocity structure associated with a dramatic plane-of-the-sky bend at a longitude of $\approx 18.5^{\circ}$. Since grouping both IRDCs to make a longer structure violates our criterion 5, we only consider the kinematically coherent part of the filament (yellow boxed region in figure \ref{fig:Candid5_with_tilt}), which is remarkably parallel to the Scutum arm in p-v space. Likewise, in figure 6 from \citet{Ragan_2014} (analogous to our figure \ref{fig:skeleton}), they represent filaments as straight lines connecting velocities measured at the tips of the filaments, while we represent filaments as sets of points whose velocities are determined by the BGPS, HOPS, MALT90, and GRS surveys. Thus, a clear and consistent description of a bone is critical, and, in future studies, we plan to continue to apply the criteria like the ones listed above to achieve consistency. Like \citet{Ragan_2014}, Wang et al. (2015) search for large-scale filaments and establish their relationship to Galactic structure after the fact. Rather than searching for filaments elongated along the Galactic plane, Wang et al. (2015) search for the longest, coldest, and densest filaments (aspect ratio >>10) in the Hi-GAL images, within the longitude range of $15^\circ < l < 56^\circ$. Wang et al. 2015 highlight nine filaments as their most prominent, with one of the nine being Nessie. Only one of their filaments (the "snake", BC\_11.13-0.12) (BC\_11.13-0.12, the "snake")  overlaps with our sample. Five other Wang et al. (2015) filaments fail one or more of our bone criteria. G24, G26, and G47 lie between 39-62 pc above the physical Galactic midplane (significantly outside our $\pm 20$ pc criteria), while G28 and G65 have aspect ratios of only around 19:1 and 38:1 (less than our 50:1 minimum aspect ratio criteria). G29 and G49 could be potential bone candidates, but without seeing p-v diagrams of the selected filaments (overlaid on log-spiral p-v fits to the Milky Way's spiral arms) it is difficult to tell whether they would satisfy our criterion 4 (within 10 km/s of the global-log spiral fit to any Milky Way arm) and criterion 6 (no abrupt shifts in velocity, of more than 3 km/s per 10 pc, within extinction feature); though Wang et al. (2014) do find velocity coherence along their filaments, they do say that, in certain clumps, the velocity gradients are much larger, creating the possibility that they might exceed our criterion 5. In future studies, we plan to follow-up on G29 and G49 to determine a) the precise number of bone criteria they satisfy and b) their association with a spiral arm in p-v space.In judging whether a filamentary cloud lies within an arm, or is highly inclined to it, the velocity of the associated gas offers the most relevant evidence. Since Wang et al. (2015) only show the correlation between filaments and spiral structure in X-Y space, we will reanalyze the most promising filaments (G29 and G49) in longitude-velocity space to more accurately determine their correlation with a spiral arm.