A NEW GENUS OF THE HEXACT1NELLID SPONGID^E. 223 



is evidently due to the presence of a greater amount of dried-up sarcode mingled with, 

 interstitial foreign substances. This darker shade, moreover, brings out in relief specks 

 and lines of pure solid white, viz. sparsely scattered minute shells of Serpula. These 

 partially are superficial and partially are deeper seated in the sponge network. In one 

 hole I observed a small Crustacean, seemingly an Amphipod. 



The exposed surface of the stem has been rubbed down moderately even, but never- 

 theless is far from smooth, being drilled by innumerable holes — in fact resembles shaven 

 cancellous texture, as is its real nature. The orifices are irregular in size and pattern, 

 though the most prominent are either circular or ovoid. The larger have a diameter of 

 nearly x- - inch, and are more widely scattered than the greatly more numerous and much 

 smaller intervening ones. Here and there also the former are so obliquely cut across or 

 worn as to form short shallow grooves or canaliculi ; whereas the finer more angular holes 

 spring from a delicate lacework, of which more hereafter. The said perforations evidently 

 correspond to the oscula and pores of other sponges. The general surface, moreover, 

 exhibits several broad but very shallow impressions or concavities Avhich traverse the stem 

 obliquely. These slightly scooped areas are seemingly traces of the deep hollows so 

 well marked between the whorls of the upper branches presently to be spoken of. 



The distinguishing feature par excellence of the branches is a series of tufts or rosettes, 

 so continuous and interwoven in the main as to present a whorl running successively 

 round from base to apex. Each branch in this particular may be likened to a thick 

 stranded coil of rope, or, still better, resembles the spiral twist of the horn of the Indian 

 Antelope (Antilope cervicapra). In some instances where two forks or branchlets arise 

 close together from a branch, before they tend to divaricate widely apart, their spiral fringes 

 in passing each other so interlock as to form bridges of union (see fig. 2, PI. XXXVI.). 

 To the naked eye, but still more manifest with a pocket-lens, the spiral tufty elevation is 

 seen to be composed of a bunch of long parallelly placed spicules, which issue from the 

 axis of the branch at an oblique angle, and slightly spread out at their free ends. The 

 radiation, however, tends upwards or chiefly towards the direction of the spire ; and thus 

 in each turn the upper border of the fringe or frill gently overarches the intervening 

 depression, its lower border proportionally less so. The apex of each branch is closed, 

 ending with a semitwist of the spicular frill. The said spicules are like so many glass 

 bristles ; but their true character is considerably masked by their being bound together 

 throughout by short transverse and oblique secondary spicula, which produce a network 

 further to be described under " Microscopic Structure." What is more plainly visible in 

 this outward examination is a superficial frosty-like network of fine spicules, these, where 

 best preserved, causing a woolly appearance ; their precise nature will again be discussed. 

 The spiral hollow between the frill differs from the latter rather in degree than in kind, 

 the relative absence of long protuberant spicula being its characteristic. The depth 

 varies, but averages a quarter of an inch. Its bareness brings out two features never- 

 theless, which are subdued in the frills. One is multitudinous oscula and pores, already 

 sufficiently alluded to in the stem ; the second, even more deeply interesting, is the presence 

 of a most lovely, delicate gossamer lacework, composed of minute spicules forming a 

 rectangular chequer. This is not everywhere intact, but sufficient traces of it exist as to 



