ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 949 



use ; did they enter by the large exhalent orifices their large-sized 

 enemies could enter also. The strong current of outflow tends to 

 drive away all enemies that are not strong swimmers. The spiculation 

 of most existing sponges must also be regarded as a powerful means of 

 defence. 



The author points out the differences in the way of defence be- 

 tween animals and plants ; the appliances of the former are either 

 mechanical, as in the oyster, or motor, as in man. Among plants 

 there is mechanical defence only, and only few have the powor of 

 making aggressive motions. 



Throughout the whole of the organic realm there seems to have 

 been a continued evolution of more rapid and varied powers of 

 motion, and with this there has been an increase in mentality ; 

 this latter, or the evolution of the brain, is a consequence of that of 

 the body, not the reverse. 



Correlation of Animals and Plants.* — M. N. Gribaut has re- 

 peated, with carps and leaves of Pofamogeton lucens, the experiment 

 of Priestley on the influence of green plants on the respiration of 

 animals, and finds that carps when alone die of asphyxia, while those 

 placed with the green plant continue to live and respire freely. 



B. INVERTEBRATA. 



Parasites of Ealsenoptera borealis.f — Mr. E. Collett gives a 

 figure of the copepodan parasite Balsenophilus unisetus, which was 

 described by Aurivillius from B. Sibbaldii, and has not before been 

 found on any other whale ; it occurs in myriads on the baleen plates. 

 In the intestines two Echinorhynchi were found in very great abun- 

 dance ; one of them is, apparently, E. porrigens Bud. ; the other 

 appears as yet to be undescribed, and may be called E. ruber. It is 

 25 mm. long, has four rows of spines on the proboscis, and ten to 

 twelve on the rostellum. The sexes were both well represented, and 

 do not appear to differ in length, colour, or general appearance. 



Mollusca. 



Morphology of the Mollusca.J — M. E. L. Bouvier has studied 

 the amphipodous Ampullaria , and an examination of its nervous system 

 has shown that this Gastropod is both chiastoneurous and zygoneurous. 

 The penis is an appendage of the mantle, and is innervated by the 

 right pallial nerve ; this is a very rare, if not unique, arrangement. 

 The epipodium is supplied by the commissural ganglia, and not, as 

 Ihering states, by the pedal ; it is therefore a pallial formation, and 

 it shows that the so-called epipodial structures are not all of the same 

 morphological significance, for some are appendages of the foot and 

 others of the mantle or body-wall. 



As in all the Ctenobranchiata the gill and false gill are inner- 



* Ccmptes Rendus, ciii. (1886) pp. 418-9. 

 t Proc. Zool. Soo. Lond., 1886, pp. 255-9. 

 j Coinptes Kcmlus, ciii. (lS86)pp. 162-5. 



