ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 503 



Anatomy of Pentastomum oxycephalum.* — J, Chatin describes 

 a form found in Alligator lucius. In treating of the integument lie 

 animadverts on the views of those who have assimilated the hypoder- 

 mis of Arthropods to an epithelial membrane, and points out that, in 

 Pentastomum at any rate, the hypodermis is merely formed by a mass 

 of protoplasm, in which a number of nuclei are scattered. The pro- 

 toplasmic areas grouped around the nuclei are not arranged along 

 one and the same horizontal line. Regularly arranged pores are to 

 be found in the integument, each segment of the body having a row of 

 them ; they are not, as some think, to be regarded as stigmata, but are 

 rather the orifices of canals from glandular organs* These last may 

 be uni- or multi-cellular ; in the former case they form an elongated 

 flask-shaped sac with a large nucleus, and in the latter with small 

 nuclei. The several portions of the intestine are not so distinctly 

 separated as in most Arthropods; the anterior is, however, distin- 

 guished from the median portion by its smaller calibre, and, in the 

 living example, one may see that the median region is generally dis- 

 tended by contents of a yellowish colour. The terminal is again 

 narrower than the median portion of the intestine. In discussing the 

 characters of the layers of which this part of the body is made up, 

 Chatin refers to the views of those who would regard the epithelial 

 zone as a layer of hepatic tissue, and directs attention to the uncer- 

 tainty of the results of histochemic investigations, and the possibility, 

 from a histological point of view, of their cells being glandular 

 elements. 



The author can find nothing in the structure of the nervous 

 system of Pentastomum which would justify us in saying that it 

 presents any aberrant arrangement. General sensibility appears to be 

 better developed than in most parasites submitted to similar conditions 

 of life, Linguatulidfe responding rapidly and vigorously to ordinary 

 chemical or electrical stimuli. Unlike flat or round worms, these 

 parasitic Arthropods appear to seek rather than avoid the light. 

 Locomotion would seem to be effected either by the aid of the spines, 

 and in the fashion of a mole, or by the creeping leech-like motion. 



Dealing with the zoological affinities of the specimens which he 

 has had under examination, the author refers to the work of Jeffrey 

 Bell, who, in order to determine two individuals found in a Boa con- 

 strictor, thought it right to examine all the species mentioned as being 

 found in Ophidians, and he not only approves of this mode of pro- 

 cedure, but says that he has himself here followed it. 



Demodex phylloides.f — Professor E. Eamsay Wright having had 

 submitted to him pieces of pork-skin largely occupied by this mite, 

 and having found no other notice of it than that in a paper by Dr. J. 

 Csokor of Vienna,! gives an abstract of that naturalist's researches. 



Three forms seem to be well recognized ; that of man, of the dog, 

 and of the cat ; and Csokor would also speak of Demodex phyllosto- 



* Ann. Sci. Nat. (Zool.) xiv. (1883) art. 2, 30 pp. (1 pL). 

 t Proc. Canad. Inst., i. (1883) pp. 275-81 (1 pi.). 

 X The reference is not given by Prof. Eamsay. 



