1867.] Zoology and Animal Physiology. 137 



Externally and internally Parasitic Acari. — M. Guerin Mene- 

 ville notes, in a letter to the French Academy, the sudden ap- 

 pearance of innumerable acari — Tyrogli/phus feculse — on his 

 potatoes. In less than eight days these little arachnidans became 

 so abundant as entirely to cover the potatoes, and form a seething 

 mass. He is at a loss to account for their remarkable and sudden 

 appearance. 



Mr. Charles Robertson, Demonstrator of Anatomy in the 

 U Diversity of Oxford, has lately described a form of acarus found 

 inside pigeons, chiefly amongst the connective tissue of the skin, 

 the large veins near the heart, and on the surface of the pericardium. 

 In some respects the acarus described agrees with Sarcojotes, but has 

 an extraordinary maggot-like appearance. The discovery of aD 

 external parasite inside an animal, in such numbers as Mr. Robert- 

 son records, is very remarkable. Colonel Montagu found such 

 acari in the gannet, and Mr. Robertson has since found them in the 

 pelican. It is exceedingly difficult to account for their appearance. 

 Are they undergoing a normal phase of their existence, or have 

 they been accidentally introduced in the cases recorded, and found 

 the habitat a # favourable one ? 



Nerve endings. — The termination of nerves in muscle is a 

 subject which still continues to call forth the energies of microscopic 

 observers. Dr. Moxon has published a paper in the last number of 

 the ' Microscopical Journal,' in which he describes the peripheral 

 termination of a motor nerve of an insect. The case described by 

 Dr. Moxon is one of considerable importance, since the insect- 

 larva (culex) is one which is plentifully distributed, and any com- 

 petent microscopist can easily lind the particular muscle and assure 

 himself of the mode of motor nerve ending. The muscle is the 

 retractor] antennae, and on it the nerve described ends in a cor- 

 puscular expansion. This is most clearly figured and described in 

 the paper, and is of course a strong case against the views of 

 Dr. Beale, and in favour of those of Continental observers, unless 

 there be one mode of termination of motor nerves in frogs and 

 another in insect larvae. Dr. Moxon cannot in any way give his 

 support to Dr. Beale's view, but thinks the question discussed 

 between Rouget and Kiihne as to the exact method of termination, 

 after the nerve has penetrated the muscle-fibre, is that to which 

 attention should be given. 



Physiology. 



Action of Prussia Acid in small quantities. — It is rarely that 

 our brothers in the Colonies contribute anything to the literature 

 of physiology, which is of real value. Mr. Ralph has, however, 

 lately read a paper before the Medical Society of Victoria of 



