66 



HARDWICKE'S SCIENCE-GOSSIP. 



empty, is partly or wholly open ; in this way a 

 <:onstant supply is kept in this miniature bag, and 

 •the pressure is always equal right up to the last atom 

 of gas. The spiral spring is of the strength that, 

 •after considerable experiment, has been found to be 

 perfect for either triple, bi-unial, or single lanterns, 



Fig. 56 



Fig- 57- 



but for special purposes] lighter or stronger springs 

 can be fitted, it being readily done by simply inserting 

 them in their seatings after unscrewing the brass 

 cylindrical cap of regulator. This valve will doubtless 

 be appreciated by all those who use the oxy-hydrogen 

 lamp with the microscope. 



ZOOLOGY. 



Parasite on Arvicola Arvensis.— lias Mr. 

 C. F. George noticed the singular situation in which 

 a parasite resembling Laelaps arvolica occurs, viz : — 

 the tail of the short-tailed field-mouse (^Arvicola 

 arvensis) ? Some time since, whilst preparing for 

 the microscope the skin of this member, I was some- 

 what puzzled by the discover>' of sundry oval bodies, 

 apparently adherent to the hairs, and which at first 

 I took to be the eggs of some creature. A closer 

 inspection, however, revealed the fact that they were 

 oval cavities, in the substance of the skin, in each of 

 which was snugly ensconced a mite, which fitted its 

 cell as closely as does the unhatched chick the egg- 

 shell. At the time I failed to distinguish the form of 

 the parasite, but was, subsequently, fortunate enough 

 to find one or two sluggishly perambulating the 

 surface, and this after being submitted to such rude 

 treatment as the following : First, the skin was 

 brushed with a very hard brush, to remove all 

 adherent particles ; it was then submitted to a scrub 

 in a strong soap lather ; rinsed ; again brushed with a 



stiff brush ; soaked in water for some hours ; stretched ; 

 and finally subjected to pressure until quite drj'. Yet, 

 upon examination, sundry of the parasites were, as 

 stated, discovered still living, although not par- 

 ticularly active. I regret that inexperience in the 

 study of these parasites precludes me from determin- 

 ing v.'hether or not this particular mite is identical 

 with that figured by Mr. George, and, unfortunately, 

 the immersion of the tail in balsam, and consequent 

 obliteration of many of the creature's distinguishing 

 features, renders identification next to impossible. — 

 Edward II. Robertson. 



AcALEPH^ (Physalia).— I have received a very 

 fine specimen of the Portuguese man of war, 

 AcalephK (Physalia), a kind of Medusa. This 

 marine animal, which is a very fine one, I have not 

 seen on our South Devon coast for over fifty years. 

 I remember gathering when a boy, after a long 

 southerly gale, nearly twenty of them, and having 

 my sleeves turned up, I placed them in my arms, and 

 was fearfully stung by them, until the doctor applied 

 remedies, which gave me relief, so I have cause to 

 remember the occurrence. I should like to know if 

 any one (reader of SciENCE-Gossip), has seen these 

 marine animals on our coast this winter. The 

 animal was found at the back of the Ness rocks, 

 Slialdon, near Teignmouth, and given to me by a 

 Mr. Woodhouse, who was staying at Col. Brines, 

 the Ness Plouse, Shaldon. I have kept it in a 

 large glass vessel, and hundreds of persons have 

 been to see it. The colour of the tentacles was a 

 beautiful deep blue, and they were about sixteen 

 inches in length. The floating part, with the body 

 of the animal was about six inches in length, of a sky- 

 blue colour. — A. y. I\. Sclatcr, M.C.S., Bank Street, 

 Teignmouth. 



Deilephila Galli. — I have a specimen of this 

 moth which was caught here in 1887. — Henry Lamb, 



j\Iaidsto7ie. 



Dysthynia Lactuosa. — I caught a single 

 specimen of this little noctua on the N. Downs, near 

 Maidstone, last summer.- — Henry Lamb, Maidstone. 



Anodonta cygnea, Linne. — To be classed with a 

 conchologist of such long standing as Dr. Henry 

 Woodward is indeed an honour, and one to which I 

 make not the slightest pretension. Mr. Williams 

 cannot have read my note with any more care than 

 did Mr. George Roberts, or he would have seen that 

 the singular number, "variety-monger " was used, and 

 he would not have placed the following atrocity, viz. 

 " variety-mongerers," in inverted commas, as if it 

 were a quotation from my note. It is only in fairness 

 to myself, believe me, that I mention a single gram 

 matical blunder. Further, the pretence is made, and 

 very clumsily made, that my wish was to constitute 

 Anodonta anatina, a variety. Now the word I used 

 with regard to this form was " variation," and it will 



