Sponyes from the Atlantic Ocean. '2M 



Microriii/ia jccusculum, Bk. {op. cit. vul. iii. j»l, Ixxxiii. 

 figs. 1-6). 



This spoiij^e was ori^nnally described Ly Dr. Bowcrhank as 

 a " Ifi/iur/u'ucidon " [oj). n't. vol. ii. p. 198). I'lie sjticules 

 are: — a partially spincd, larjL^e, skeleton acuatc ; a smooth, 

 acuate ; |K»inted, subskelcton acerate ; a small, entirely spincd 

 acuate, and an anijulate or bow-shaped equianehorate. 



Loc. Island of Harris, Hebrides. 



Two specimens ot" this thin laminiform sponge were dredged 

 uj) on board the ^ Porcupine,' viz. at station 2/5, in 374 

 fathoms, near Cape St. \'incent, and at station 61, in 114 

 fathoms, near the Faroe Islands, respectively — the former, of a 

 reddish colour, spreading over the flat surfaces of a piece of Co- 

 rallistes Boicerhan/cii, and the latter, almost colourless, over a 

 Terebratule. Both are characterized by possessing a smooth, 

 acerate, subskeleton-spicule, and a much greater develo])ment 

 of the spines round the bases of the two forms of acuates 

 respectively, than in any other part ; while the spicule-illus- 

 trations given by Dr. Bowerbank agree better with the colour- 

 less specimen on the Terebratule than with the red one on the 

 piece of Corallisfcs. The spicules in the latter are not so 

 large, the acuate skeleton-spicule less curved towards the 

 base, and the equianehorate larger in the arms and more 

 pointed at the ends, so as, laterally, to resemble a bow, of 

 which the anterior arm of each end, being by recurvation closely 

 approximated at their points, would form the cord or string. 

 In both the tricurvate is absent ; and the subskeleton-spicule, 

 being acerate, smooth, and nearly straight, con-esponds more 

 with that of ILdicltomlria phunosa tlian with that of the 

 ^licrocionina generally, in wliich it is acuate. It may be 

 questioned hereafter whether the differences noticed between 

 the above-mentioned forms of M.jecuscuhaa are sufficient to 

 constitute two sjiecies. Colour alone in sponges is seldom of 

 much specific value. 



Microciona longispicvlum, n. sp. (PI. XII. fig. 1, A, and 

 PL XV. fig. 31,a,/>,c.) 



General form thin, laminar, hirsute. Colour tawny. Sur- 

 face hairy. Pores and vents not seen. Spicules of two kinds, 

 viz. skeleton- and flesh-sjiicules. Large skeleton-spicule 

 long, smooth, curved, thin, globularly inflated or bulbous at 

 the fixed extremity, smocjth througliout, 16()-18()()ths inch 

 long by 2-1800ths' inch in diameter at the bulb (PI. XV. 

 fig. 31, (i). Subskeleton-spicule smooth, acuate, curved, 



