The generic name _Huttonia_, suggested by Sternberg[747] in 1837, is applied to cones which closely resemble _Macrostachya_ in habit, but differ—so far as our scanty knowledge enables us to judge—in the arrangement of the members. The student must refer to Weiss[748], Solms-Laubach[749] and other writers[750] for a further account of these types, and of another rare and little-known form of cone, called by Weiss Cingularia[751]. Macrostachyan cones have been found attached to stems of _Calamites_ which are included in the sub-genus _Calamitina_ (p. 367). The larger size of _Macrostachya_ as a distinguishing feature is not always a safe test; some cones which belong to _Palaeostachya_ [_e.g._ _P. arborescens_ Sternb.] and _Calamostachys_ (_e.g._ _C. Solmsi_) are much thicker and larger than the majority of species of these two genera. It would appear from the examples selected to illustrate the connection between strobili and vegetative shoots, that the _Annularia_ type of branch usually bears cones which conform to the genus _Calamostachys_ (_Stachannularia_); while the Asterophyllitean branches—_Calamocladus_—are associated with _Palaeostachya_ and _Macrostachya_. But this rule is not constant, and we are not in a position to speak of cones of a particular type as necessarily characteristic of definite types of Calamitean shoots. • • • • • Although it is admitted by the great majority of Palaeobotanists that the Calamites were all true Vascular Cryptogams, the older view that some members of the Calamarieae are gymnospermous has not been given up by Renault[752]. This observer has recently described some seeds which he believes were borne by Calamitean stems; he admits, however, that no undoubted female cones of _Calamodendron_ have so far been found. In view of the unsatisfactory evidence on which Renault’s opinion is based, we need not further discuss the questions which he raises. [The following specimens in the Williamson Cabinet in the British Museum, may be found useful in illustration of the structure of _Calamites_. _Stems._ (i. _Arthropitys._) _Young twigs and small branches_ 1, 2, 6, 10, 14, 19, 116*, 1002, 1007, 1020. _Older stems_ (_transverse sections_) 15–17, 62, 77–87, 115 _a_, 117*, 118*, 120, 122*–124*, 1933 A, 1934, 1941. (_Tangential sections_) 20, 24, 26, 37, 38, 49, 90, 91, 130, 138, 1937, 1943. (_Radial sections_) 20, 20 A, 21, 22, 48, 65–68, 83–91, 137*, 138*, 1937. (ii. _Arthrodendron)_ 36, 37, 38, 52, 54. _Roots._ 1335, 1347, 1350, 1356. _Strobili._ i. _Calamostachys Binneyana._ 991, 996, 997, 1000, 1003, 1005, 1007, 1008, 1011, 1013, 1016, 1017, 1022, 1023, 1037 A, 1043. ii. _C. Casheana._ 1024, 1025, 1587, 1588. iii. _Palaeostachya vera._ 110, 1564, 1567, 1569, 1579, 1583.] III. Pith-casts of Calamites.