402 COLLECTIONS FROM MELANESIA. 



resemblance in external characters and in this remarkable structural 

 point between Mr. Carter's species and the present specimens, I 

 assign the latter with little doubt to that species, although Mr. 

 Carter has not given the measurements of the spicules. 



Eab. Port Jackson, 0-5 fms. 



Distribution. Ceylon (Carter) ; Kurrachee (coll. Mm. Brit.). 



The absence of this species from the hauls made in the tropical 

 waters of Northern Australia perhaps indicates that its natural 

 habitat is in subtropical seas, like those of Northern India and Port 

 Jackson. 



TOXOCHALINA*, g. n. 



Chalinidae with well-developed horny fibre arranged rectangularly. 

 Spicules, a skeleton acerate and a tricurvate acerate (" Pogen," 

 German) flesh-spicule. 



Obs. The tricurvate flesh-spicule distinguishes this genus from all 

 other Chalinidae ; the only parallels for the occurrence of a flesh- 

 spicule in this group with which I am acquainted are found in the 

 species Halichondria palmata of Johnston, lately (Ann. & Mag. Nat. 

 Hist. (5) x. p. 109) redescribcd and assigned by Mr. Carter to the 

 genus Chalina, and Spongia ( Desm acid on, Ehlers) compressa, Esper, 

 also referred (I. c. p. 112) by Mr. Carter to Chalina, and in a species 

 described by 0. Schmidt (' Meerbus. Mexico,' p. 76) as Rhizochalina? 

 fibulata, which has bihamates. The fact of an intimate connexion, 

 which seems to have been thus already discovered, between the 

 Chalinidse and Desmacidinidae, appears to receive confirmation from 

 the present cases of the occurrence of a tricurvate flesh-spicule in 

 members of the former family. 



32. Toxochalina folioides. (Plate XLI. figs, m-m".) 

 Desmacidou folioides, Bowerbank, P. Z. S. 1875, p. 295. 



In one Powerbankian specimen from New Guinea and one ' Alert ' 

 specimen from Australia the form is vallate, produced by the lateral 

 union of a series of tubes ; the other ' Alert ' specimens agree with 

 the type (see Powerbank, I. c.) in its external form, and the former 

 specimens may be termed var. vallata. This is a true Chalinid, 

 although the amount of horny material in the fibre is no more than 

 enough to unite the spicules into a tough and elastic mass, and is 

 not visible outside the spicules. I have detected in the type speci- 

 men of this species small, smooth, finely-pointed, tricurvate acerates, 

 about •01 by '001 millim. in size, in the dermal membrane ; I have 

 not yet detected them in the subjacent tissues, though this has been 

 dono for another specimen of the species in the Powerbankian col- 

 lection (from New Guinea). The skeleton-spicules vary from rather 

 tapering cylindrical, with rounded ends, to tapering acerate, with 

 sharp ends, size about -11 by ^0012 millim. in the typical, and *16 

 by '0085 millim. in the Port Darwin specimens. The New-Guinea 



* From Gr. t6$oj>, a bow ; and xaXu-os, a thong. 



