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Show 130 200L0GICAL COLLECTIONS MADE DURING [Jail. 4, The species appears to stand near to the sponge figured by Schmidt as V.johnstonii in 1870 (/. c. supra), and there set down as a variety of the form which he described in 1862 (Spong. adr. Meer. p. 78, pi. vii. fig. 14), but which is obviously specifically distinct from that of 1862, on the ground of its almost totally different spicu-lation ; for to the latter are attributed acerate and stellate forms as its complement, while the 1870 species1 possesses a spinulate and two forms of spiro-spinular spicules {cf. Carter, Ann. and Mag. N . H. [5] iii. p. 149, w h o suggests this solution of the discrepancy between the two descriptions). It differs from this species chiefly in the absence of a short stout spirospinular flesh-spicule, and in the much greater fineness of the thin spiro-spinular form (the diameter being as 1 to 3 and the length as 1 to 2 of those of that species). It seems to be also not far removed from Clione lobata, Hancock (Ann. and Mag. N . II. [2] iii. p. 343, pi. xii. figs. 4, 8, and [3] xix. p. 239, pi. vii. fig. 6 ), but differs from it in the stoutness of the spinulate spicule and the globose character of its head, and in the greatly inferior diameter and the less frequent angulation of the spiro-spinular spicule. That species is described as being dark in colour wheu dry; but as the colour when in spirit is not mentioned, it is not safe to compare it with V. carteri as to this point. Sollas's C. subulata2 differs from this, apart from the colour (which is unfortunately not mentioned by him), in the greater stoutness of the body and greater distinctness of the head of the spinulate ; its length and the length and characters of the spiro-spinular agree almost exactly with those of our species. Relations of the Homy and Siliceous Sponges of Magellan's Straits and the neighbouring Coasts to thoseof other Seas.-I have gone somewhat more into details, in comparing the sponges described in this paper with allied forms, than is usual in papers of this kind. But I felt this to be desirable for two reasons:-1st, because the characters of the Sponge-fauna of these localities have hitherto been hardly investigated at all, and it is therefore important to ascertain its relations to those of other localities; 2nd, because in certain groups, chiefly in the Renierida, the possible range of variation of individual species seems to have been not clearly ascertained, owing mainly to the imperfection of our present knowledge of the relative classificatory values of the different characters; and as the nearest allies of the species here described were mostly from the Northern and Equatorial Atlantic, it was to be expected that in the passage to the southern part of the Atlantic Ocean we should find indications of the nature and extent of the changes which species have undergone (if that is the right way of expressing the relation) in making the same or the converse passage. In the present state of our knowledge, the genera of the above groups of sponges as a rule embrace many species and are widely distributed. This is due probably to the want of a more minute subdivision of the genera, but also certainly to some extent to the great age of the group in time, and to its members being but little limited 1 This should be renamed, and would be well called Vioa schmidtii. 2 Ann. N. H. [5] i. p. 65, pi. ii. figs. 26-28. |