growth, but the next bud of the same side was merely a minute tubercle. It may accordingly 

 be concluded that in this species there is only one vvell developed bud at a time. 



The following species of Loxosoma are referable to Mortensen's genus Loxocalyx; though 

 the specific characters are by no means well ascertained in all cases; and it is uncertain whether 

 they all deserve specific rank : 



Loxosoma alatum Barrois 1877. 



Loxosoma cochlear Schmidt, 1876. 



Loxosoma leptoclini Harmer, 1885. 



Loxosoma ncapolitanum Kowalevsky, 1866. 



Loxosoma pes Schmidt, 1878 (which has been regarded as a synonym of L. alatum). 



Loxosoma ra ja Schmidt, 1876. 



Loxosoma tcthyae Salensky, 1877. 



Of these, L. alatum, L. cochlear, L. pes, L. raja and L. tetJiyae have been recorded 

 as occurring on various Sponges. In most of these species the stalk appears to be less than 

 twice the length of the calyx, but in L. tcthyae it is generally at least twice as long. In this 

 respect the 'Siboga' specimens agree more nearly with that species than with any of the others. 

 No adequate figure of L. tcthyae appears to have been published; but it is worth calling 

 attention to certain figures, by O. G. Costa, which have not, I think, been previously cited in 

 the accounts of this species, but which are of interest as being probably the earliest figures of 

 any species of Loxosoma. The figures in question were published in Cosïa's "Fauna del Regno 

 di Napoli", "Zoofiti", the title-page of which bears the date 1838. The real dates of publication 

 are given in 'Isis', 1846, Heft IX, p. 718; and relying on the information there given and on 

 the dates which occur on the edges of the sheets, the Section headed "Genere Tezia; Tethya 

 Lamk." was really dated Nov. 18, 1843 (pp. 1 — 8), Jan. 3, 1844 (pp. 9 — 16), and May 14, 1844 

 (pp. 17 — 24). On pp. 11 and 12 of this Memoir Costa gives an account of certain polyp-like 

 structures which he regarded as belonging to the Tethya. The figures 1, 2 and 5, at the top 

 of PI. I, illustrating the description, are perfectly characteristic representations of Loxosoma 

 tcthyae-, figs 1 and 5 showing the general form of the calyx and stalk, and fig. 2 being a 

 good representation of the foot, and showing further the arrangement of the ectoderm-cells of 

 the stalk in eight longitudinal rows; a feature to which I called attention in my Memoir on 

 Loxosoma l ), without being at that time acquainted with Costa's figures and description. It need 

 hardly be remarked that as Costa regarded the Loxosoma as a part of the Sponge, he did 

 not give it any generic or specific name. 



The calyx of L. tcthyae, as seen in Costa's figures, is relatively narrow, and is not 

 furnished with thin lateral expansions. There can thus be little doubt that the 'Siboga' specimens 

 are not to be referred to that species. From L. leptoclini they differ in the absence of the 

 group of cells, at the distal end of the calyx, characteristic of that species 3 ), as well as by the 

 much longer stalk. L. raja Schmidt 3 ) has a specially broad calyx; but its broadest part is at 



1) Harmer, S. F., 1885, Quart. J. Mier. Sci., XXV, p. 262. 



2) Ibid., PI. XIX, fig. 2. 



3) Schmidt, O., 1876, Arch. mikr. Anat., XII, PI. I, fig. 1. 



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