ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 167 



sure, the respiratory movements, and the muscular contractions in 

 swimming. In the eel the normal frequency of beats is greater than 

 that of the respiratory movements, in Bar bus fluviatilis and Telestes 

 mutkdlus it is less. Stimulation of the vagus nerve produces diastolic 

 arrest ; cutting it results in acceleration. Warming the water results in 

 increasing the rapidity of the cardiac rhythm up to a maximum which is 

 not exceeded ; when the temperature is lowered, the frequency diminishes. 



Mutation-phenomena in Animals.* — M. Nussbaum calls attention 

 to cases such as the differences in the optic chiasma in nearly related 

 species of fishes. In one the right is uppermost, in another the left is 

 uppermost ; and there are many similar instances in regard to which an 

 apparent abruptness of change must be postulated. In other words, 

 there is a certain discontinuity in the adult results, though these results 

 are reached by continuous ontogenetic development. But it is hardly 

 to details of this sort that de Vries 1 concept of mutation refers. 



Natural History of the Lumpsucker.f — Theodore Gill gives an 

 interesting account of the peculiarities, habits, and relationships of the 

 lumpsucker. The skeleton is very remarkable because of the extreme 

 reduction of the bones and the inverse development of cartilage. All 

 the bones, however, are there, but existent in a reduced state or as thin 

 membrane-like pieces fastened to the cartilaginous mass. The relation- 

 ships of Cyclopterids are with the Sculping or Cottidse, which have the 

 bones firm and well ossified, and very little persistent cartilage. A 

 review is taken of the different genera. 



The lumpsucker is widely distributed in the North Atlantic, both 

 horizontally and vertically. It frequents cold waters : it is a " bottom 

 fish," though it may be found swimming freely ; it is rather lethargic, 

 but very active and fierce in the breeding season ; it feeds on crustaceans, 

 medusae, worms, and shell-less molluscs. 



The spawning season lasts from February to June. The male keeps 

 a watchful guard over the eggs, not merely defending them from 

 intruders, but aerating them by waving his pectoral fins and spouting 

 water from his mouth, as Fulton has shown. An account of the larva? 

 is given, and the vivid paper ends with a discussion of the lumpsucker's 

 dubious palatability. 



Respiratory Mechanism in Elasmobranchs.J — A. D. Darbishire 

 has elucidated several interesting facts in connection with the breathing 

 in various types. In the dogfish, water is drawn into the mouth and 

 spiracle by the expansion of the whole phargyngeal region ; water is pre- 

 vented from entering the gill slits by their automatic closure, the gill 

 covers being in part passive agents in determining the respiratory cur- 

 rent. The differences between the dogfish and ray in their respiratory 

 mechanism all relate to the flat shape and ground habitat of the ray. 

 In the former the greater part of the inhaled water enters through 

 the mouth, in the latter through the spiracle — solely through it when 

 the fish is at rest. In the dogfish water never enters solely through the 



* Mutationserscheinuugen bei Tieren. (Bonn, 1906) 24 pp. 

 t Smithsonian Misc. Coll., iv. (1907) pp. 175-94 (16 figs.). 

 \ Journ. Linn. Soc, xxx. (1907) pp. 86-94 (3 figs.). 



