Why have the large number of expected remnants not been detected?
is quoted by Davies in such a way to make the reader think his estimate of the number of Galactic SNRs is correct. But in the original paper, this was a rhetorical question, in the context of discussing the 1973 estimate by Mathewson & Clarke that there should be 340 visible remnants in the Larger Magellanic Cloud. Clark & Caswell immediately follow this by giving several reasons why the 1973 estimate is unreliable (the Mathewson & Clarke estimate has been discussed earlier, in Section 10.3). The relevant paragraph from the original paper is: Thus two anomalies require explanation. Why have the large number of expected remnants not been detected? Is it reasonable that E0/n should differ so greatly from our estimate for the Galaxy? Both anomalies are removed if we assumed that the N(D)-D relation has been incorrectly estimated owing to the small number of remnants (4) used. As already mentioned in Section 10.3, Clark & Caswell’s suspicion was subsequently proved to be correct. But Davie
