HARDWICKE'S SCIENCE-GOSSIP. 



01 



Fig. 42. Spicules from Prhnnna verticulosa, x 75. 



Mr. Cole gives the following brief and simple 

 receipt for preparing and mounting these spicules : 

 — " Boil in strong liquor potasses for three or four 

 minutes, and then wash repeatedly in distilled 

 water until the latter passes off quite colourless ; 

 then mount in Canada balsam : if the specimens are 

 to be mounted dry for the paraboloid, make a cell 

 of the proper depth, coat the inside of the cell with 

 thin gum-water ; when this is dry, breathe on it to 

 moisten its surface, then place your spicules in the 

 cell, turn the slip over, and tap the back so as to 

 knock out any that may be loose ; put on your thin 

 cover, and all is done but asphalting the cell and 

 labelling the slide." 



"It might not be difficult," says Dr. Johnston, 

 " but it is beyond my province, to trace the gradual 

 increase and consolidation of these spicula through 

 many intermediate species to the horny flexible axis 

 of the Gorgonia, where it has become such au effi- 

 cient support to the whole soft envelope as to claim 

 not improperly the name of its skeleton ; thence to 

 the stony axis of the coral and having there reached 

 its maximum of development, I might on the other 

 hand have marked its progress towards degene- 

 ration until it became again only a partial support, 

 such as we find it in the naked middle portion of 

 the Pennatulidce, more especially in some of the 

 foreign and less typical species of that family." 



The following is a list of the British Gorgoniadee 

 from the work of the author last mentioned. 



1. Gorgonia verrucosa, somewhat fan-shaped, much 

 and irregularly branched, the branches cylindrical, 

 fiexuous, barked when dry with a white warted 

 crust ; segments of the cells unequal, obtuse ; 



habitat deep water ; abundant along the whole of 

 the south coast. 



2. Gorgonia pinnata, when living, a little thicker 

 than sewing cotton, of a cream-white colour, the 

 polypes white with dull granular pinnated tentacles ; 

 fouud in thirty fathoms water in the Isle of Skye. 



3. Gorgonia placomus — has been mistaken for a 

 coralline — of a reddish-brown colour, has its branches 

 disposed in a dichotomous order and flatfish form ; 

 they bend irregularly towards one another, but 

 rarely unite ; very rare, ou south coast. 



4. Gorgonia auceps, the Sea- willow — Keratophy ton 

 dichotomum ; caule et ramulis leviter compressis ; 

 of a yellow-white when fresh, drying of a deep 

 violet ; found only in deep water, and very rare. 



5. Gorgonia jlabellum, the common Sea-fan, has 

 been admitted into the British fauna on very 

 insufficient evidence. 



The Primnoa differs from the Gorgonia in having 

 a hard stony axis, approaching to that of the true 

 corals. 



Primnoa lepadifera, eighteen inches high and as 

 thick as a swan-quill ; found in Shetland, Norway, 

 Lapland, and the White Sea ; crust whitish, covered 

 with pear-shaped polype-cells. 



Isis hippuris, owes its name to the resemblance 

 it bears to the Equiseta, mares-tails ; is found on 

 the east coast of Scotland and Orkney Islands. 



Si 



Fig. 43. Coral polypes, x 25 (" tpanouis a des degres divers "). 

 After Lacaze Duthiers. 



The Gorgoniadee were not generally believed to 

 be luminous, but the researches of the men of 

 science who conducted the deep-sea exploration in 

 H.M.S. Porcupine, in i860, show that those dredged 

 up from great depths, 557 to 5S4 fathoms, were 

 brilliantly phosphorescent : " The Pennatulce, the 

 Virgularice, and the Gorgonia> shone with a lambent 

 white light, so bright that it showed quite dis- 



