Crossword-Solution: INTERAMBULACRAL 15 letters, 1 clue 🏆 scrabble score: 21

These intervals are called the interambulacral spaces; but while in some orders they are occupied by larger plates and prominent spines, as in the Sea-urchin and Star-fish, in others they are either comparatively insignificant or completely suppressed, as in the Crinoids and Ophiurans.

Taking the orders in their rank and beginning with the lowest, we find in the Crinoids that the dorsal system preponderates, being composed of highly complicated plates, and developed to such a degree as to form in many instances a stem by which the animal is attached to the ground, while the ambulacral system is limited to a comparatively small area, and the interambulacral system is wanting.

Here the ambulacral and interambulacral systems have taken a great preponderance over the dorsal system, and the same is the case with the Holothurians, in which the same structure is greatly elongated, the dorsal system being thus pushed out as it were to the end of a cylinder, while the ambulacral and interambulacral systems run along its whole length.

The broad zones, representing the interambulacral system, are composed of large plates, supporting a number of hard projecting spines, while the narrow zones, forming the ambulacral system, are pierced with small holes, arranged in regular rows, (Fig.

These zones converge towards the summit of the animal, meeting in the small area which here represents the dorsal system; this area is filled by ten plates, five larger ones at the extremity of the interambulacral zones, and five smaller ones at the extremity of the ambulacral zones.