if you post in reply to previous posts rather than create a new post it is easier for all to keep track and to review previous info.

Most Manx illegitimates were known by their father's name (and had been since 17th C if not earlier) - under a manx law only repealed in 20th C any illegitimate birth by legitimised by marriage within 2 years (this was important for property inheritance). The IGI adopted the English (and I presume the American law) and filed under the mother's name.