dredged up from the Gulf of Manaar . 45 



that, in some instances, they were identical with the latter ; 

 and now they have presented themselves in Microciona fasci- 

 sjjicidifera, which seems to be a very common species in the 

 Gulf of Manaar, as there are many specimens of it on the 

 Melobesian nodules. This, however, is not the only instance 

 in which the flesh-spicules may be developed together in 

 groups, as we see by the rosettes of inequianchorates, also 

 another common feature of Esjyeria ; and I have little doubt 

 that bihamates may be produced in the same way, particularly 

 after considering the illustration of Hymedesmia zetlandica, 

 Bk. (Brit. Sponges, vol. iii. pi. xxix.), in which the biha- 

 mates are not single, as is usually the case, but in groups 

 like the tricurvates &c. It should, however, be remem- 

 bered that these spicules are often developed singly as well 

 as in groups in their cells ('Annals,' I. c. pi. x. figs. 11 

 and 12). We must view the sheaf-shaped bundles, then, 

 I think, as " flesh-spicules " closely allied to, if not identical 

 with, tricurvates ; and therefore they may occur in any kind 

 of spiculiferous sponge ; hence it is not strange that we 

 should find them in a Microciona, where the tricurvate is such 

 a common flesh-spicule. 



Mr. Sollas has proposed for them the name of " trichites " 

 ('Annals,' 1880, vol. v. p. 133), which it would be as well 

 henceforth to adopt, as they are evidently not peculiar to one 

 kind of sponge, and may occur in a great number ; so that 

 they should, for convenience of description, have a fixed 

 designation, although, as I have above stated, they seem to 

 me to be but another form of the tricurvate. 



Hymerhaphia unispiculum, n. sp. 

 (PI. IV. fig. 8.) 



Laminiform, extremely thin, hirsute, spreading. Cream- 

 colour. Spicules of one form only viz. large, setaceous, 

 smooth, acuate, curved chiefly towards the blunt end, which 

 is hemispherical and a little more in diameter than the shaft, 

 from which it is differentiated by a slight constriction, 70 

 by l|-1800th (PI. IV. fig. 8). Size variable ; that of the 

 specimen about \ inch in horizontal diameter. 



Hah. Marine. On hard objects. 



Loc. Gulf of Manaar. 



Obs. Hymerhaphia unispiculum is not so remarkable for 

 the form of its spicule, which is common to many species, as 

 for there being no other, in which respect it resembles Hyme- 

 desmia simp>licissima, Bk. (Brit. Sponges, vol. iii. pi. lxxx. 

 fig. 1). It seems to me questionable, however, if this is not 



