It is worth while to examine the value and definition of certain of the older generic or sub-generic groups, for there is much difference in the usage of the terms, and in the interpretation of their rank and value. This is especially the case with Acaste and Phacopidella, for the author of the latter name wrongly included in it such forms as Ac. downingiae and others of a diverse type, though they differed in important particulars from the species Ph. glockeri Barr. which he chose as the type of Phacopidella as above observed (see Glockeria). Other new and old generic terms appear to have been also used in too broad a sense, and there is no general agreement as to their limitation.

In furtherance of an intention expressed in a former paper (Geol. Mag., Vol. LXIII, 1926, p. 143), I propose, in this communication, to give some statistics of the anal variations in 542 cups, all of which are referred to the genus Ulocrinus. Additional details are also given of similar variations in 130 cups referred to Hydreionocrinus. Fifty of the latter have already been dealt with elsewhere (Trans. Geol. Soc. Glasgow, vol. xvi, pt. iii, 1917–18, p. 383), but to complete the survey of the anal area in the four groups of cups for the present, it is thought advisable to include them here. The classification here adopted is the same as that given for Eupachycrinus calyx and Zeacrinus konincki, namely:—

The chemical environment of vesuvianite and grossular is typically revealed in their associated minerals, calcite, diopside, scapolite, and wollastonite, characteristically developed under the physical conditions prevailing in thermal metamorphism.

A Porose corals have, with few exceptions, received little attention in Britain since the publication of works by P. M. Duncan and R. F. Tomes, during the latter half of last centary. The newer methods of investigation by means of thin slices and serial sectioning, so successfully employed by Drs. Stanley Smith and W. D. Lang, and others, in the Rugosa, were not then in use, and so very little is known of the internal structures–the only basis for classification and comparison–or of the developmental stages of the Aporosa.