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THE VOYAGE OE H.M.S. CHALLENGER. 
and in contact with the epithelium, and are generally distributed through the choano- 
some, in the walls of the chief canals lying tangentially. 
Colour. — (?), probably originally cream-yellow, now stained with magenta. Size, 
about 30 mm. in length by 15 mm. in height. 
Hahitat. — OffHavanna; depth, 100 fathoms. 
Remarks. — This sponge presents a very close superficial resemblance to Cnemidias- 
trum jpluristellatum, Zittel (Lithistidse, p. 110, Abhandl. d. k. baier. Akad. d. Wiss., Bd. 
i., 1878 ; Cnemidium stellatum, Quenst., Jura, p. 676, pi. cxxviii. figs. 6, 7). The oscules, 
with the associated superficial canals, and the short, much tuberculated desmas, are 
similar in both. 
Family III. Cladopeltid^. 
Genus 1. Siphonidium, 0. Schmidt. 
Siphonidium ramosum, 0. Schmidt. 
Leiodermatium ramosum, O. Schmidt, Spong. Atlant. Gebiet., p. 21, pi. iii. fig. 1, 1870, 
„ „ Carter, Ann. and Mag. Nat. Hist., ser. 4, vol. xii. p. 439, 1873. 
., ,, Zittel, Abhandl. d. k. baier. Akad. d. Wiss., Bd. b p. 103, 1878, 
Siphonidium ramosum, 0. Schmidt, Spong. Meerb. Mexico, p. 28, pi. i. fig. 8, 1879. 
Leiodermatium ramosum, Vosmaer, Bronn’s Tbierreicbs, Bd. ii., Porifera, p. 290, 1885. 
Sponge. — Similar to Siphonidium capitatum. 
Spicules. — I. Megascleres. 1, Desmas, similar to those of Siphonidium capitatum. 
2. Oxystrongyle, style-like, strongylate termination finely granulated, 0'45 by 0’02 mm. 
Habitat. — Florida, 125 fathoms ; Sombrero, 240 fathoms ; Morro Light, 212 fathoms. 
Remarks. — The similarity of Siphonidium ramosum and Siphonidium capitatum has 
already been commented on. It only remains to add a few words in explanation of the 
change in the generic name. The genus Leiodermatium, as founded by 0. Schmidt, 
originally included two species generically different, Leiodermatium ramosum, 0. Sch., 
and Leiodermatium lynceus, 0. Sch.; on recognising this Schmidt proposed the new 
name Siphonidium for the species Leiodermatium ramosum, Zittel {loc. cit., p. 122) 
having previously redefined the genus Leiodermatium on the type of Leiodermatium 
lynceus, 0. Sch. Vosmaer objects to this nomenclature and states that as Leiodermatium 
ramosum was the first-described species, it must stand as the type of Leiodermatium, 
and a new generic name must be found for Leiodermatium lynceus. This seems to me 
hypercritical. Schmidt’s two species were described, one immediately after the other, in 
the same publication, and neither was specially indicated as the type ; an author has of 
