The coat of arms of Most Rev. Robert Deeley installed on February 14 as the 12th Bishop of Portland, Maine.
The right side of the shield is divided by a wavy line to suggest water. This theme continues in the lower portion with alternating silver and blue waves, suggesting deep waters and his home see of Boston. Resting on the waters is a scallop or pilgrim’s shell, which, for Bishop Deeley, represents both baptism and a special homage to Pope Benedict XVI, who chose Bishop Deeley for the episcopacy and whose own shield also includes a shell. The silver color of the shell represents the purity of God. Above this is a lion, which Bishop Deeley considers to be emblematic of his family. The front half of the lion is rendered in black and the hindquarters are in red, with the claws and tongue taking the opposite colors.
The left side of the shield, representing the Diocese of Portland, features the diocesan coat of arms, which includes a field of blue with a scattering of gold pine cones. It is based on an ancient French royal family coat of arms and reflects the French roots of the diocese, which date back to 1604.
At the time of his episcopal ordination last year, Bishop Deeley chose as his motto “Veritatem Facere in Caritate,” which he translates as “living the truth in love” (Ephesians 4:15).
Design: J. Noonan
Artwork: L. Nicholson
EXARANDORUM 
Quite nice crest! Good thing that the personal part did not change.
Though some remarks.
1 – In the explanation we could read when mgr. Deeley became auxiliarian bishop of Boston we also learned that the bishop introduced a meaning in his procession cross: Marial elements. In my own practise I always advice against such plans. Such a cross is only to point out to “I am a bishop”, or with double bar: “I am an archbishop”.
I always ask a bishop elect: draw what cross you want, but never give significance to it.
Perhaps the practice of Dean Sullivan and Cardinal Cordero is most wise: they have their own model-crosses.
However: the most beautiful crosses are from the late Bruno Heim.
2 – The shell is silver, partly on silver bars. We’d better advoid this. Why not gold, bases on a good explanation?
What is the medal hanging on the bottom of the shield ? No explanation of it.
That badge indicates the Bishop is a member of the Sovereign Military and Hospitaller Order of St. John of Jerusalem, Rhodes and Malta, more commonly known simply as the Knights of Malta.
I believe if the Bishop were the Grand Master of the Order, then it would be proper to add the insignia, but otherwise it is tacky and not at all grounded in any heraldic norms I have ever heard of.
Then you may not have done quite as much research on the topic as is necessary. There is a whole system and protocol for members of the Order (and the bishop is a Conventual Chaplain, a relatively highly-placed ranking) to display the Order’s insignia in their own coats of arms. In fact, Pope Benedict XV ruled that no other chivalric orders should be displayed in the heraldic achievements of bishops and cardinals EXCEPT the insignia of the Order of the Holy Sepulchre or the Order of Malta. It is a commonly accepted practice for any member of an order (lay or cleric) who has a coat of arms to display the insignia of the order in their full achievement of arms. While many bishops choose not to do so many choose to exercise that option. It’s far from tacky and it is ABSOLUTELY well grounded in long-standing heraldic norms. I suggest that since you haven’t heard of them that this is an area where you might enjoy doing a little research in order to find out more about it. You’ll be surprised!