Report on the zoological collections made in the Indo-Pacific Ocean ...

'402 COLLEGTIUNS FROM MELANESIA.resemblance in external characters and in this remarkable structuralpoint between Mr. Carter's species and the present specimens, Iassign the latter with little doubt to that species, although Mr.Carter has not given the measurements of the spicules.Hah. Port Jackson, 0-5 fms.Distrihution. Ceylon {Carter) ; Kurrachee {coll. Mus. Brit.).The absence of this species from the hauls made in the tropicalwaters of Northern Australia perhaps indicates that its naturalhabitat is in subtropical seas, like those of Northern India and PortJackson.TOXOCHALINA*, g. n.Clialinidae with well-developed horny fibre arranged rectangularly.Spicules, a skeleton acerate and a tricurvate acerate (" Bogen,"German) flesh-spicule.Obs. The tricurvate flesh-spicule distinguishes this genus from allother Chalinidse; the only parallels for the occurrence of a fleshspiculein this group with which I am acquainted are found in thespecies Halichondria palmata of Johnston, lately (Ann. & Mag. Nat.Hist. (5) X. p. 109) redescribed and assigned by Mr. Carter to thegenus CJialina, and Spongia {Desmacidon, Ehlers) compressa., Esper,also referred {I. c. p. 112) by Mr. Carter to Chalina, and in a speciesdescribed by 0. Schmidt (' Meerbus. Mexico,' p. 70) as Rhizochalina?Jibidata, which has bihamates. The fact of an intimate connexion,which seems to have been thus already discovered, between theChalinida) and Desmacidinidae, appears to receive confirmation fromthe present cases of the occurrence of a tricurvate flesh-spicule inmembers of the former family.32. Toxochalina folioides. (Plate XLI. figs, m-m".)Desmacidon folioides, Boiverbank, P. Z. S. 1875, p. 295.In one Bowerbankian specimen from New Guinea and one ' Alertspecimen from Australia the form is vallate, produced by the lateralunion of a series of tubes ; the other ' Alert ' specimens agree withthe type (see Bowerbank, /. c.) in its external form, and the formerspecimens may be termed var. vallata. This is a true Chalinid,although the amount of horny material in the fibre is no more thanenough to unite the spicules into a tough and elastic mass, and isnot visible outside the spicules. I have detected in the type specimenof this species small, smooth, finely-pointed, tricurvate acerates,about -04 by "001 millim. in size, in the dermal membrane ; I havenot yet detected them in the subjacent tissues, tliough this has beendone for another specimen of the species in the Bowerbankian collection(from New Guinea). The skeleton-spicules vary from rathertapering cylindrical, with rounded ends, to tapering acerate, withsharp ends, size about -11 by '0042 millim. in the typical, and "16by '0085 millim. in the Port Darwin specimens. The New-Guinea* From Gi". t6%ov, a bow ;and xaXtvos, a tbong.