356 FRESH FACTS [November 1899 



near the water's edge, reached out and caught hold of the tip of an overhanging 

 leaf, and climbed into it. With their hind legs both male and female held the 

 edges of the leaf, near the tip, together, while the female poured her eggs into 

 the funnel, the male fertilising them as they passed. The jelly in which the 

 eggs were laid was of sufficient firmness to hold the edges of the leaf together. 

 Then moving up a little further more eggs were laid in the same manner, the 

 edges of the leaf being sealed together by the hind legs, and so on up the leaf 

 until it was full. As a rule two briar leaves were filled in this way, each 

 containing about 100 eggs." Even more interesting, however, is the subsequent 

 development. 



How Copepods Swim! E. W. Macbride. "The movements of Cope- 

 poda," Q%iart. Journ. Micr. Sci. xlii. 1899, pp. 505-507. In the freshwater 

 Cyclojts the first antennae assist in the slow movements, and the belief is 

 general that copepods propel themselves by their first pair of appendages. 

 Prof. Macbride observed at Plymouth that the slow gliding movements of 

 marine copepods are effected principally by the second antennae, the gnathites 

 likewise assisting, notably the second maxillae. The cniick movements,? on the 

 other hand, are effected entirely by the simultaneous action of the thoracic 

 feet. 



Clamps in Animals. Otto Thilo. " Sperrvorrichtungen im Tierreiche," 

 Biol. Centralbl. xix. 1899, pp. 504-517, 13 figs. Dr. Thilo points out that one 

 must serve some apprenticeship in engineering before one understands the 

 animal body, and his ingenious essay bears this out. He leads us from the 

 valves of the heart to the device which keeps the globe-fish's self -inflation 

 from collapsing, but he is at his best in expounding clamps for rigid structures. 

 From the clamp of the spine of Monacanthus (a fish from the Red Sea coral- 

 reefs), we pass to more complex cases in Triacanthus and the stickleback, and 

 the leverage-system which works the snake's fang is not forgotten. It is an 

 essay for a dull afternoon, so ingenious is it ; but it is with some misgivings 

 that we are forced to conclude that in addition to mathematics and meteorology, 

 statistics and spectroscopy, psychology and philosophy, and much more, the 

 complete naturalist must also learn engineering. 



Variations in Jellyfish. E. Ballowitz. " Ueber Hypomerie und 

 Hypennerie bei Aurelia aurita, Lam.," Arch. Entivickelungsmechanik, viii. 1899, 

 pp. 239-253, 1 pi. This common jellyfish seems to be an animal well deserving 

 the attention of those who follow the modern statistical method of the study 

 of variations. It is normally a tetra-partite creature, but sex-partite, pent- 

 partite, and, more rarely, tri-partite forms may be found thrown up on the 

 beach. Sometimes the variation is very consistent throughout ; thus a tri- 

 partite individual had a three - cornered mouth, three genital pockets, six 

 marginal bodies, etc. ; but, often, there is less uniformity and transitional forms 

 occur. Some of the variations may be traceable to the Ephyra-stage, but most, 

 according to Ballowitz, must have an earlier origin. Here is evidently a case 

 for experiment to assist observation. 



Digestion in Fishes. Emile Yung. " Recherches sur la digestion des 

 poissons (Histologic et physiologie de l'intestin "), Arch. zool. exper. vii. 1899, 

 pp. 121-201, 1 pi. Prof. Yung has made many histological observations and 

 physiological experiments in regard to digestion in fishes, and has removed 

 some of the prevalent vagueness. The formation of pepsin seems rigidly con- 

 fined to the stomach-sac and to a particular region of it. 



The Problem of Equilibration. Th. Beer. " Vergleichend - physio- 

 logische Studien zur Statocystenfunction. ii. Versuche an Crustaceen (Penaeus 

 membranaceus)" Pfliiger's Arch. f. Physiol, lxxiv. 1899, pp. 364-382. When 

 the statocysts of Penaeus are extirpated, the animal can no longer keep its 

 balance in swimming ; it falls to one side or to the bottom. 



