764 SCIENTIFIC RECORD FOR 1885. 



Professor Camerano does not think that a " theory of radiation is suflB- 

 cient" to account for all the phenomena observed. {Nature^ v. 32, p. 77; 

 see, also, reply by Mr. Meldola in same vol., i)p. 172, 173.) 



Temperature maxima for marine animals. — A series of experiments 

 has been undertaken by Dr. J. Frenzel for the determination of the 

 maximum heat under which certain animals can live. The first experi- 

 ments were commenced by subjecting some to a temperature of 40° C. 

 This was supported by a Holothurian for two hours. A Diopatra died 

 in about five minutes; a large tectibranchiate gastropod (Pleurobran- 

 chsea meckelii) exhibited at first lively movements, but after five min- 

 utes became torpid, although it was not killed; four minutes were 

 enough for a lobster-like crustacean (Scyllarus). "As the Holothurian 

 was the largest of the animals experimented on, the author points out 

 that, although the chief reason for its power of resistance might be 

 sought for in its size, yet the others were conquered too rapidly." Con- 

 sequently, it was to be inferred that the Holothurian is really capable 

 of resisting heat to an vmusual degree. 



Further observations were made at a starting point of 30° C, and of 

 the animals thus experimented upon an Ophiuroid ( Antodon) began to 

 break up in two seconds ; the Diopartra survived for eighteen hours; a 

 chsetopod worm (Terebella) showed the effect of heat at 25° C. ; a tecti- 

 branchiate gastropod (Sea-hare or Aplysia) lived at 26°; a pectinobran 

 chiate gastropod (Murex) "bore 30° for a long time;" and a Scallop 

 (Pectera) " showed some resistance;" a Scyllarus " could bear 25°, bat 

 died slowly at 26<^, and more quickly at 27° ; " and a prawn (Palsemon) 

 "died at 26° ;" a fish (the Sea-horse or Hippocampus) "bore 27° well, 

 and lived for an hour at 30°." 



In fine, "many marine animals were found to bear high degrees of 

 temperature for an astonishingly long time, as Actinice, Murex, Tethys, 

 and Aplysia. But it is not yet certain what heat they can permanently 

 bear. It is also important to discover how winter animals comport 

 themselves towards increase of temperature, and especially animals 

 such as the Heteropoda and Phronima, which are quite wanting in the 

 summer ; from what we know we must suppose that at the beginning 

 of summer, when the temperature of the sea becomes raised, they make 

 their way to greater depths, where the heat is less." {Arch./, gesammt. 

 Physiol, V. 36, pp. 458-466 ; J. B. M. S. (2), v. 5, pp. 791, 792.) 



PROTOZOANS. 



RMzopods. 



Differentiation in Amcehas. — Although proverbially protean and un- 

 stable, the Amcebeans nevertheless exhibit differences which aptly dis- 

 tinguish them into forms generally considered to be of specific value; 

 such, differences have been especially insisted upon by Dr. A. Gru- 

 ber. Dr. Gruber contends that " there are a number of separate 

 and exactly definable AmoebsB which do not pass into one another,'' 



