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Show 1905,] SPONGE CLATHRINA CONTORTA. 5 was really a specimen of variabilis, while the specimen of contorta of which the spicules were figured (I. c. figg. 8, 9, 10) was really a specimen of complicata; and that amongst nine of Bowerbank's specimens examined by me I have found four distinct species confused together-to wit, complicata, variabilis, coriacea, and " Ascelta spinosa Lendenfeld" : I think it is not necessary to say more in support of the statement that Bowerbank's species contorta was of absolutely no systematic value whatever, but represented merely an ill-defined jumble of different species. In 1872 Haeckel, in his ‘ Kalkschwamme ' [2], used Bowerbank's specific name contorta for a sponge which he described in detail. Haeckel pointed out quite rightly that the external characters of contorta as set forth by Bowerbank were no guide whatever to its identification, since a quite similar mode of growth characterises other Ascons. Haeckel therefore diagnosed contorta by details of its spiculation. The diagnosis given is incorrect in two points, namely, in stating that the monaxons possess a lance-head at their distal extremity, and that the gastral rays of the quadri-radiates are " curved oralwards" ; two statements that lead me to suspect that Haeckel's material of contorta was, like Bowerbank's, contaminated by admixture of Leucosolenia complicata. Haeckel, in his description, also affirmed, in his usual manner, definite characters in the spiculation without taking into consideration the variability which is so marked a feature of the sponge. It is a puzzle to me how Haeckel arrived at the definition which he gave of A scanclra contorta, since the specimens named and identified by him which I have seen do not agree with his description, and belong, indeed, to other species-a fact which easily explains any errors of description on his part. It is even more mysterious that Haeckel should have considered his contorta identical with Bowerbank's contorta, since, of Bowerbank's specimens examined by me, eight in all, not one agrees with Haeckel's diagnosis! These enigmas are not, however, of importance to the present enquiry. Taking Haeckel's description as it stands, and allowing for a certain margin of inaccuracy, I have been able without difficulty to refer to Haeckel's Ascandra contorta a sponge extremely abundant on the Mediterranean coasts of France, and occurring elsewhere also. As I have stated in a previous memoir, I consider that where previous writers leave us is doubt as to the characters of a species, Haeckel's description fixes the application of the name. I will proceed now to describe the sponge which I regard as the true contorta, and then to consider the synonymy and application of the name. Ascandra contorta H. is a species which, for reasons stated elsewhere [4, &c.], I refer to the genus Clathrina Gray (1867). It has a closely reticulate mode of growth, equiangular triradiate systems, collar-cells with basal nucleus, and parenchymula larva; all these being characters which make up my diagnosis of the genus Clathrina. |