114 



HARDWICKE'S SCIENCE-GOSSIP. 



ZOOLOGY. 



Parasites on Hydra. — While examining an un- 

 usually large specimen oi Hydra fiisca the other day, 

 I was surprised to notice that the tentacles and body 

 of the polyp were infested with what I suppose to be 

 parasitic infusoria. These creatures are concavo- 

 convex, shaped like a mussel-shell, and have numer- 

 ous vacuoles. They move rapidly all over the body 

 and tentacles by means of cilia which are of large 

 size and beautifully evident. Although I watched 

 them for some time I did not observe any leave 

 the body of their host, nor could I find any trace of 

 them in the surrounding water. I have examined 

 many hydra obtained from various sources, but have 

 never come across these parasites before. Perhaps 

 some microscopic reader will be kind enough 

 to give me the name of this creature, or, at any 

 rate, tell me if they are of frequent occurrence. 

 I might mention that the hydra were by no means 

 incommoded by their guests, but appeared quite 

 indifferent to their presence ; so that when the 

 parasites glided over the extended tentacle that 

 delicate organ remained outstretched, but instantly 

 contracted when an animalcule of smaller size came 

 in contact with it. — J. O. B. 



Notes on Frog-spawn and Tadpoles. — The 

 following notes extracted from my day-book of last 

 year may form a useful addition to Mr. Robson's 

 interesting article on frog-spawn in Science-Gossip 

 for March. Frog-spawn was first seen early in the 

 morning of March 13th ; the thermometer through 

 the day was 49^° F. The average weight of an 

 ovum when found was about 5*4 grains. The tad- 

 poles when they emerged (March 19th, in open 

 air) measured \ of an inch, and weighed i grain ; 

 the breadth across gills to their ends -j'j of an inch. 

 So soon as they escaped from the glairy egg they 

 sank to the bottom and looked as if dead, but when 

 touched merely curled themselves up into a ball of 

 the same size as that seen in the advanced ovum. 

 Soon, however, they became extremely active, swim- 

 ming vigorously about, but were unable to sustain 

 themselves long in mid-water. They ate very little 

 of the albumen of the egg, but soon began to devour 

 decomposing aU;oe, and then decaying water plants, 

 &c. Pretty bright eyes appeared at the end of 

 March, when the tadpoles measured \ of an inch in 

 length. Some fortunate, or rather unfortunate tad- 

 poles, developed into perfect little frogs before the 

 others, were seized upon and immediately devoured 

 by the latter — no doubt from jealousy. The rapidity 

 of the development of the frog from the egg is in 

 exact proportion to the temperature of the water 

 — supposing abundance of food to be supplied. — 

 C. Francis Yoittur. 



Whitby Field Naturalists' Club. — This, 

 newly-formed club has already started, and has had 

 a weekly list of papers since the first of January. W^e 

 wish the membei"s success. 



A List of European Birds. — A List of Birds 

 of the Western Palrearctic region has been compiled 

 by Mr. H. E. Dresser, F.L.S., F.Z.S., as a check- 

 list for labelling, and for reference in making ex- 

 changes of birds and eggs. As no such list previously 

 existed, there is no doubt that the present one will, 

 prove very useful. 



The Weather of 1880.— Last year we noticed 

 "The Weather of 1879," by Mr. Edward Mawley, 

 F.M.S., we have now the satisfaction of noticing 

 the continuation of the work. It is the author's 

 intention to publish his report annually. The present 

 pamphlet is upon the same plan as last year's, and 

 is evidently carried out with great care. To agri- 

 culturists, gardeners and meteorologists generally 

 it is of great value. 



Injurious Insects. — The "Report of Observa- 

 tions of Injurious Insects," edited by L. A. Omerod, 

 F.M.S., &c., for 1881 is to hand. The great insect 

 attack of the year was that of the larva; of Tipttla 

 olcracca, commonly known as "daddy longlegs." 

 There was also severe damage in some localities 

 from the larvre of the carrot fly and onion fly ; the 

 chief injuries of the season being from larvce of the 

 order Dipteia, which are known to be most prevalent 

 in wet vegetation and in wet ground, such as was 

 caused generally throughout the country by the 

 continued rain of 1879. 



Transparent Burnet Moth. — The moths men- 

 tioned in Science-Gossip for February, having been 

 sent for inspection to Mr. Bjrchall of Douglas, that 

 gentleman says : " They are certainly not the Irish 

 form, viz. Nubigena ; it is possible they are examples 

 of the typical European Minos." Perhaps some 

 reader collecting in the neighbourhood next summer 

 (should we fortunately have one) may be induced to- 

 visit the spot. — W, Gain, Tiixford. 



Tpie Laughing Gull. — The bird recently killed 

 in the neighbourhood of Newmarket and recorded as 

 the Laughing Gull [Lartis atricilla) proves to be the 

 common Blackheaded Gull (Z. ridibundus) ; see 

 "Field "for 26th of March. Premature announce- 

 ments of this kind are greatly to be regretted, as it is 

 impossible to correct them in all the numerous publi- 

 cations into which the report is copied, and the con- 

 fusion and uncertainty thus created can only be 

 appreciated by those who in after years have to run 

 these phantoms to earth. The present instance seems 

 more than ordinarily inexcusable, happening so near 

 Cambridge, where some of our best ornithological 

 authorities reside, who I am sure would willingly 

 have determined the species if at all doubtful. — T. S, 



