dredged up from the Gulf of Manaar. 57 



cavated cavities of the Melobesian nodules, has led me to 

 designate it " socialist The specimen of Samus anonymus, 

 to which I have alluded I first found, together with a Cliona, 

 in an excavated cavity 5 and knowing of no other sponge but 

 a Cliona that made such cavities, I viewed the Samus as an 

 intruder; but now that, in the Melobesian nodules, I have 

 found Samus anonymus filling the excavations alone, I am 

 constrained to admit it as a new genus of the Eccoelonida. If 

 such shall be found to be the case with Thoosa, then also 

 there will be no doubt of its excavating power ; but the speci- 

 mens of it that I have seen have been so minute and so mixed 

 up with other sponges, that at present I consider this only 

 a provisional determination. Had I obtained it as I did the 

 following species, which is equally minute, viz. by solution 

 of the piece of Melobesia containing it in nitric acid, I might 

 have seen the sarcode holding the spicules ; but in the dried 

 state in which I found it I could only infer its existence from 

 the contracted appearance of the little mass. On account of 

 its presence in specimens of many other sponges from the 

 excavations of the Melobesian nodules that I have mounted 

 in Canada balsam, it seems to me to be very plentiful, but 

 in very minute portions. The larger spicule, no. 1, also 

 exists iti the neighbourhood of the Seychelle Islands, as 

 represented in the ' Annals ' of last year (vol. iii. pi. xxix. 

 fig. 21). 



Dotona pidcliella, n. gen. et sp. 

 (Pi. V. fig. 24, a-d.) 



General form (when dry and contracted) a minute sarcodic 

 mass densely charged with the spicules of the species. Colour 

 white. Spicules of three forms, viz. : — 1, a cylindrical 

 curved shaft, round at the ends, which are microspined, 

 interrupted throughout by apparently annular lines at equal 

 distances from each other, but which, by alteration of the 

 focus, are found to be parts of a spiral ridge formed of micro- 

 scopic points, united longitudinally and respectively by strise, 

 which thus extend throughout the spicule, 12 by H-6000th 

 (PI. V. fig. 24, a, d) ; 2, acuate, simple, smooth, hair-like, 

 very fine, 20-6000ths long (fig. 24, b) ; 3, flesh-spicule, 

 minute, consisting of a straight shaft spined over both ends 

 divergingly, and in a ring round the centre, 2 by ^-6000th 

 (fig. 24, c). Spicules mixed together generally; very vari- 

 able in size and in various stages of development ; the flesh- 

 spicules very minute and sparse. Size of specimen about 

 l-8th inch in diameter. 



Hab. Marine. In excavated cavities of the Melobesian 



