The last Group in Series Y, the coins of Group M, exhibit evolutionary change as well as the variations that are typical for this series. Most of the design differences are to be found on the reverses of these coins, the obverses differing sometimes only in the design of the forelock. The head above the pony is discontinued, and in its place there is an ornament of reversed S shape swelling at the top to the outline of a curved leaf, creating a void which is then filled by a solid crescent of similar shape to the void. Half of these interior shapes are free-floating, while the rest merge into the bottom of the reversed S shape of the ornament.

The evolutionary aspects of this group is expressed by two sub-groups: in M1, the lash attaches to the mane ornament, and the pony's ears are shaped like the number "3"; in M2, the lash attaches to the driver's forehead, and the ears are laurel-leaf shaped. There is one coin (79), that is transitional. In this coin, the lash attaches to the mane ornament as in Subgroup M1, but the pony's ears are laurel-leaf shaped as in Subgroup M2. As mentioned in the introduction to Series Y, these very coins gave me my first glimpse of how the overlapping evolutionary changes in the designs could furnish a tighter chronology of the Coriosolite coins than the more conventional methods could, and this made it possible to expand the six classes into fifteen groups, with additional subgroups.

The chronology is as follows:

Group M	Coins (75, 76, 77, 78), 79, 79 var., (80, 81, 82).
M1	(75, 76, 77, 78).
M1/M2 transition	79.
M2	79 var., (80, 81, 82).

The obverse of Coin 75 is similar to the previous coin.

On the reverse, the lash is similar in design to the previous coin, but contains six X's. Where the lower line connects to the tip of the mane ornament, the lines of the lash run parallel. At the front of the lash, the lines are pincer-shaped and end above the "Union Jack" banner. The central part of the mane ornament connects with the bottom of the reversed S. The ears of the pony, although roughly approximating the "3" shape, do not show this as clearly as on the following coins. The front legs of the boar are drawn in the usual manner.

The obverse of Coin 76 is different in that the forelock is not connected to the forehead, but floats in front of it. The central "S" shape of the forelock is heavier than usual, the top terminating in a curl, the reinforcing lines surrounding only the bottom, the ending in the middle of the "S" shape. There are considerably fewer curls on the head than is usual.

On the reverse of Coin 76, the lash contains three X's. The two lines of the lash become a single line, which curves around to meet the tip of the mane ornament. The front end of the lash and the banner are similar to the previous coin. The central upper part of the mane ornament is not an extension of the lower part, but is an isolated crescent. This feature continues for the next two coins. The ears of the pony are clearly "3" shaped.

The obverse of Coin 77 is similar to the obverse of Coin 75.

On the reverse, the lash contains five X's. The one above the mane ornament utilizing the upper line of the lash as one of the diagonals. In other respects, the lash and banner are similar to the previous coin, although the banner is set inward so the inner line of the lash points to the outer corner of the banner.

The obverse of Coin 78 has very few curls on the head, and they are poorly executed, askew, and badly spaced. Being unique in the hoard, much pertinent information is missing from the coin. What is present resembles the previous two coins. An identifying feature of the reverse die is the lower line of the boar's head turning downward at a right angle to become the upper front leg.

The obverse of Coin 79 is similar to that of Coin 75, although the forelock is of the same type as on Coin 76, but is connected to the forehead, and the central part of the design is thinner. The reverse of Coin 79 shows the transition from Subgroup M1 to Subgroup M2: The ears of the pony resemble laurel leaves, but the lash still connects to the mane ornament, of the same design as on Coin 75. In this case, the lower line curves backward to meet the ornament in the usual manner, but the upper line is retained, and curls upward in opposition. The lash contains five X's, and is connected to the banner on either side of the central bead. The upper section of the boar's hind leg is missing, and the lower line of the boar's head curves downward and forward to become the upper section of the foreleg.

Coin 79 var. marks the beginning of Subgroup M2, and presumably only differs from Coin 79 in the lower line of the lash connecting to the driver's forehead.

The obverse of Coin 80 is similar to that of Coin 75.

The reverse of Coin 80 has a lash that contains four X's, and ends just above the right side of the banner, which consists of a St. George's (Greek) cross superimposed on two opposed double chevrons. The upper section of the boar's hind leg is again present, and the foreleg is the same as in the previous coin.

The obverse of Coin 81 resembles the previous coin, but there is a short hair between the lower ear-spiral and the back of the neck.

The reverse of Coin 81 omits the curl on the upper line of the lash; now that the lash connects to the driver's forehead, the engraver finally realizes that this curl no longer opposes another element; as it did when it curved forward to the mane ornament. The method of bringing the two lash lines together in a single line, as on Coin 76, is resumed. The lash, containing five X's, ends just above the centre of the "Union Jack" banner. The boar is again engraved in the usual manner, with a straight line for the top section of the foreleg.

The obverse of Coin 82 differs from the previous coin by the lowest outer hair on the head, near the neck, which has no curl.

The reverse of Coin 82 has a novel driver's head: the nose is short, and extending from the bead are two backward curls, the whole motif resembling the number "3." The lash contains four X's, the single end extending back in a slight curve downward to just in front of the middle of the driver's crest, where it turns sharply downward to meet the forehead. The front of the pony and the banner are the same as on Coin 79. The mane ornament is of the same type as on Coin 75, but is larger, and the central part is heavier. The boar is again of the usual type. Although not mentioned as being especially common by Rybot, I have seen more examples of this coin than any other in this group.

This is the end of Series Y, the continuum of six groups comprising Classes I and III. This series did not contain the smooth evolutionary changes that was so characteristic of Series X, and it was marked by some faltering and indecisiveness of purpose; however, there were some fortunate results, and the final designs of the reverses were certainly very beautiful, particularly in the style of the pony. This was enhanced by the production technique, which allowed remarkable crispness on many of the coins, so much that it is possible to see the faint marks left by the engraving tools on the die in some cases.