106 



HARDWICKE'S SCIENC E-GOS SIP. 



grasshopper-warbler, whose uote I had heard iu a j 

 certain field on several successive evenings. While 

 thus engaged, I saw a cuckoo, followed by a grey 

 wagtail, flying over a neighbouring wood. After a 

 few minutes the wagtail returned, and I went in 

 that direction, but failed to find her nest. On the 

 following evening I was again engaged seeking the 

 grasshopper warbler's nest, and I again saw the 

 cuckoo pursued by the wagtail. Once more I 

 sought for the wagtail's nest, and again failed. 

 Next year, however, I hope to meet with better 

 success, and to ascertain for a fact whether or not 

 the custom of the Cuckoo is to visit its eggs and 

 young periodically, and, if so, how often. I should 

 be much obliged if some other lovers of natural 

 history would help me. I should take great 

 pleasure in vindicating the character of the Cuckoo 

 from the charge of deserting its young to the 

 mercies of strangers. 



I have heard it said that the physical conforma- 

 tion of the Cuckoo incapacitates it from the work 

 of incubation, and that, consequently, its maternal 

 instinct teaches it to deposit its eggs to be hatched 

 iu the nests of other birds. According to my idea, 

 it would seem a painful blot on the Cuckoo if it did 

 not feel anxious for the welfare of its young, and 

 manifest its watchfulness and care by frequent 

 visits. I would much rather believe that the 

 Cuckoo pays daily visits to its eggs and young ; 

 and, when they are all fledged, gathers them, 

 though reared in diflTerent homes, into one family, 

 and then takes them, under its fostering care, to 

 distant lands. G. E. R. 



THE GLASS-ROPE SPONGE, 



IN the April part of the "Annals of History," 

 Dr. E. Gray has the following strictures on 

 my papers en Ilyalonema in the February and March 

 numbers of Science-Gossip : — 



"Mr. E. Kitton makes some remarks on Paly- 

 tlioa investing the Glass-rope Sponge, and figures 

 some of the animals growing on the surface of 

 a ray's ova-case, evidently considering that this 

 proves their parasitic nature. He mentions a se- 

 cond case in which they are growing on a riband 

 frond of some species of Algae. I regard both these 

 instances as proving just tlie contrary — ' the Alga 

 had become entangled with the glass-rope.' The 

 egg-case of the Ray is often to be found attached 

 by its elongated ends to the glass-rope. I believe 

 the figure only represents some of tbe eggs or buds 

 of the Palythoa growing on its surface, to M'hich 

 they have become accidentally attached, and that 

 they will never come to perfection, so as to form 

 a crust or develop the ropc-likc spicules. 



" My reason for believing this to be the case is, 

 that the polyps are more isolated ; they arc of different 



sizes, some being very small ; some are crowded one 

 upon the other, so as deform their shape, very unlike 

 the uniform crust they form on the glass-rope ; and I 

 have no doubt of their being incapable, from theii' 

 position, of developing the usual rope. 



" Mr. Kitton states that the examination of the 

 Palythoa, when [found apart, has enabled him to 

 ascertain the spicules peculiar to it. Eigs. 21 and 

 25 of his previous paper appear to be the only forms 

 of spicula really belonging to the Palythoa. He 

 omits to state that the spicules are siliceous, like the 

 other spicules found on the rope and bark of Hyalo- 

 nema, which have not hitherto been found on 

 Palyt hoa ; and the two forms he mentions from a 

 polyp only differ from those found on other parts of 

 that coral iu being thicker and more spinous. 



"In a previous number of Science-Gossip, Mr. 

 Kitton figures Hyalonema, fig. 19, with its para- 

 sitic sponge and the various spicules he has observed 

 in different parts of it (figs. 21—31). These figures 

 are good, except fig. 20, representing the ends of a 

 broken fibre of the rope. He does not seem to be 

 aware that Hyalonema is more common without its 

 parasitical sponge at the top than with it ; but the 

 specimens with the sponge were formerly more 

 sought for by travellers, and brought to England, 

 whilst the Russian specimens, being collected by 

 naturalists, were chiefly without this parasite, and 

 now we constantly receive them without any appear- 

 ance of sponge covered with living polyps up to the 

 tip." 



In reply to the remarks which Dr. Gray has done 

 me the honour to make on my papers, I beg to say 

 that I am still unconvinced of the parasitic nature 

 of tbe sponge, or that the Palythoa is non-parasitic. 

 Until I saw the specimens belonging to the Rev. 

 J. Crompton, I was very much inclined to believe 

 that the Palythoa was an integral portion of the 

 sponge ; but when I saw it growing on the alga as 

 stated, and this not entangled on the glass-rope, but 

 carefully twisted round it, and below it some fine 

 twine, I could only come to the conclusion that the 

 long anchoring spicula did not belong to the Paly- 

 thoa. The ova-case of the Dog-fish was attached to 

 the glass-rope by one of its long tendril-like filaments, 

 but the rope itself had none of the Palythoa growing 

 upon it : in both cases the crust and tubercles 

 were as well developed as when growing on the 

 glass-rope. 



Dr. Gray says I omit to state that the spicules in 

 the Palythoa are siliceous ; if, however, be will refer 

 to my first paper, he will find 1 particularly allude to 

 their siliceous nature, considering that to be evi- 

 dence of their spongeous origin. 



My reasons for considering the sponge and rope 

 as one organism, are, that many of the forms of 

 spicula occurring in the heads of the sponge arc 

 also found between filaments forming the rope, par- 

 ticularly the spiculate cruciform, the attenuated 



