2U 



HARDWICKE'S SCIENCE-GOSSIP. 



the rarer forms of Enteromorpliee are as puzzling to 

 distinguish as some of the Cladophora. Experience 

 and the microscope are here, as in many other 

 instances, alike indispensable. 



Among the various phenomena connected with 

 marine algse is that of the glaucous tints which appear 

 on the fronds of some species when viewed under 

 the influence of sunlight in shallow water. Those 

 which possess this remarkable property most 

 distinctly are Padina pavonia, Chondncs crispus, and 

 Cjjstoseim ericoides. The latter species, which 

 upon being drawn out of the water is a brownish- 

 yellow, appears, under water, as thongh it were 

 painted the most beautiful cerulean blue, or even 

 ultramarine. I have often wondered what is the 

 cause of this iridescence, which in the genus 

 Cysfoseira is peculiar to the species ericoides, or 

 the heath-like Cystoseira. I have sought for an 

 explanation of the marvel in vain, and begin to 

 suspect that a series of chemical experiments 

 alone will lead to a solution of the mystery„ 



In the early part of last summer, during two or 

 three of my visits to Hope's Nose, I met with 

 a large number of the bladder-like fronds of that 

 curious deep- green plant known as Rivularia niiida. 

 They were attached to the sides and upper surfaces 

 of two large rocks near high-water mark. Not 

 requiring any specimens of this plant, I left the 

 whole quantity undisturbed ; but this season I did 

 not meet with a single frond, and now, of course, I 

 regret my forbearance, for the plant is rather rare, 

 and it is always agreeable to be able to furnish 

 acquaintances with specimens of rarities. Near 

 the rocks on which the Rivularia was growing, 

 there is a large pool at low-water mark (partly 

 overshadowed by high rocks on three sides), 

 in which I have often enjoyed a swim as the tide 

 was rising, and in which I had the opportunity 

 of witnessing an instance of the extraordinary 

 rapidity of growth in the large species of Laminaria, 

 commonly known as "Sea-furbelows." Three 

 years ago, when I first bathed in this pool, the 

 bottom was quite full of large plants of Laminaria 

 digitata, but no specimen of L. hdbosa, or Sea- 

 furbelows. The following season I was surprised 

 to find several : one of them was a monster, and 

 as its long puckered stem and waving laciniated 

 frond interfered with my natatorial enjoyment, I 

 took the trouble to pull the great plant away from 

 its place of growth. The bulbous root was bigger 

 than both my fists, the large puckered stem was 

 over four feet in length, and the numerous lacinia- 

 tions which crowned the stem, when spread out, 

 formed a circle about 12 ft. in circumference. Even 

 admitting that this plant arose from an old root- 

 stock, unseen by me the season before, the whole 

 plant must have been the growth of little more 

 than six months. In the same pool where this great 

 carweed was grown, I observed specimens of the 



deep-water plants Desmarestia aculeata and 

 D. ligulata. They were growing side by side on a 

 portion of the rock some distance under the over- 

 hanging ledges, and so they were out of reach ; the 

 wash of the sea there being so strong, that even at 

 low water there is no time to creep under and make 

 a grasp at the plants before the wave comes up and 

 deluges one, as 1 have experienced to my discomfort 

 more than once. I saw both species of the Desma- 

 restia there last year, but this season I had no 

 opportunity of visiting the place when the tide was 

 favourable for a search, and so I am not aware 

 whether those rare plants are still growing in their 

 former habitat. One other very interesting plant 

 remains to be mentioned, and that is Callopkyllis 

 laciniata, formei'ly Rhodymenia laciniata. This 

 beautiful species is perennial, and it is also propagated 

 by tetraspores, which are produced in cloudy 

 patches on various parts of its membranous fronds, 

 and by spores which are developed in proper leaflets 

 put forth from the margins of the laciniations for 

 this special purpose. I have frequently picked up 

 fragments of this species on the Abbey Rocks in 

 Torbay and at Paignton ; but this spring I found it 

 at Meadfoot, east of Torbay, — on one occasion with • 

 tetraspores, which is tlie rarest form of fructifica- 

 tion, and soon afterwards I was fortunate in finding 

 a very highly-coloured specimen with the spore- 

 bearing leaflets, besides numerous barren specimens. 

 What it is which causes some species to put forth 

 the primary form of fructification, and others to as 

 constantly produce the secondary, or tetrasporic 

 form, is among those mysteries of nature which 

 prevail in the Cryptogamia, or flowerless plants, 

 and which we at present are bound to recognize, 

 though the wisest among us cannot explain. 



Wide is the field for speculation, but narrow and 

 limited is our knowledge, in this, as in many other 

 departments of natural history. The more I reflect 

 on these things, the more I am tempted to think, 

 write, or speak ; but it is time for me to ask others 

 what they think, and — " I pause for a reply." 



THE MANTIS, OR PRAYING INSECT. 



THIS insect, about which "E.G." makes inquiries 

 at p. 215, is exceedingly interesting from many 

 points of view, and well deserves a passing notice. 

 By some modern systematists the genus is placed in 

 the order Orthoptera, by others among the Dicty- 

 optera. In any case it must take rank near the 

 wonderful stick-and-leaf insects, with which indeed 

 it was confounded by the earlier naturalists. 



The external appearance of the Mantis is so 

 singular, and they offer so many peculiarities of 

 structure, that they may be easily recognized among 

 their congeners. The long, narrow body, the wing- 

 cases traversed by numerous veinlets and embracing 



