348 ANNUAL RECORD OF SCIENCE AND INDUSTRY. 



scaphocephaly is applied to the so-called boat-shaped cra- 

 nium, of which a new modification has lately been described 

 from Holland. In this the cranium is elongated or laterally- 

 compressed, and extended into a keel or ridge in the sagit- 

 tal direction. 15 A, October 17, 1874, 515. 



EFFECT OF PARASITISM IX THE ANIMAL SERIES. 



Among the communications in the zoological section of 

 the French Association, recently held at Lille, was one by 

 Professor Vogt, on the effect of parasitism in the animal se- 

 ries, in which he endeavored to show that the most varied 

 forms, belonging to very different groups, could in their 

 degradation by parasitism lose in succession their differ- 

 ent organs, so as to resemble each other very closely, and 

 to render it very difficult to determine, without critical 

 study and investigation, to what group a particular object 

 belongs. 



In this connection he mentions the Entoconcha digitata, the 

 sacculines, and the trematodes, the starting-points of which, 

 namely, the embryo, are very different, as belonging to en- 

 tirely distinct groups. They, however, by successive retro- 

 grade metamorphoses, come to resemble each other to such 

 a degree that, without the assistance of embryology, they 

 could be classed in the same group, although the one be- 

 longed to the gasteropod-mollusca, the others to the cirrhi- 

 pedes and the trematodes respectively. 



Professor Giard, in remarking upon this paper, stated that 

 he had already arrived at a similar conclusion in studying 

 ascidians. 8 B, September 5, 1874, 237. 



CHANGE OF VOLUME OF FISH IN SWIMMING. 



According to a statement of results already established by 

 an investigation by Harting, conducted by means of peculiar 

 and very delicate apparatus, the chief causes of the change 

 of volume of the bladder in fish, and consequently of the 

 volume of the fish, are: 1, Variation of pressure upon the 

 fish, resulting from an upward or downward movement made 

 by the fins, the bladder being entirely passive in the case; 



2, the separation and absorption of the gases contained in 

 the bladder, as well as their removal through the air-duct; 



3, the movement in breathing, not perceptible with all fishes; 



