40 SUMMARY OF CURRENT RESEARCHES RELATING TO 



5. Liamellibranchiata- 



Visceral Ganglion of Pecten.*- W. J. Dakin describes the large 

 complicated visceral ganglion, whose great development is correlated 

 with the extent of the area of innervation, and due to the reduction of 

 the more anterior parts of the animal, the absence altogether of the 

 anterior adductor, and the corresponding increase of the posterior muscle 

 and other parts. 



Dakin describes the lobes of the ganglion, the innervation of the 

 osphradium, the central neuropil (an intricate mass of neurofibrils) and 

 the cortical layer of motor ganglion-cells, and the minute structure 

 generally. 



The scallop is very sensitive to the presence of starfishes, which are 

 recognized by the olfactory sense, and not by touch or sight. The 

 osphradia and abdominal sense-organs do not appear to play any visible 

 part in the perception of starfish. 



The orientation of the animal is apparently controlled by the otocysts. 

 The movements of the velum and adductor muscle are co-ordinated, and 

 are concerned in several important functions, as swimming, orientation, 

 and expulsion of reproductive cells. 



Removal of the abdominal sense-organ has no visible effect on the 

 perception of vibrations in the water. The function of this organ is 

 probably different from that of the osphradium, and may be the regu- 

 lation of currents in the pallial cavity. 



Cleansing Oysters.f — Fabre-Doniergue has made an interesting and 

 practically important series of experiments to show that oysters may be 

 kept for eight days or more in filtered water, frequently renewed, without 

 losing in weight or in vital resistance or in appearance. In this way the 

 cleansing of the pallial cavity from deleterious micro-organisms can be 

 secured without affecting the market value of the ovsters. 



Feeding Habits of Oysters.! — Fabre-Domergue refers to the belief 

 that oysters feed selectively on Diatoms, Infusorians, Copepods, and the 

 like, rejecting by their labial palps what is unsuitable, while the gills 

 exhibit no filtration. This view is weakened by experiment. Oysters 

 placed in water badly contaminated with recognizable faecal matter 

 ingested large doses of this. A bacteriological inquiry should extend 

 to the intestinal contents of the oyster. 



Arthropoda. 

 a. Insecta. 



Colour-sense of Hive-bee.§— John H. Lovell has made a number of 

 very interesting experiments bearing on the much-discussed question 

 whether hive-bees can distinguish colours. His conclusions are the 

 following : Bees easily distinguish colours, whether these are artificial or 

 natural. They are more strongly influenced by a coloured slide than 

 by one without colour. Bees which have been accustomed to visit a 



* MT. Zool. Stat. Neapel, xx. (1910) pp. 1-40 (2 pis.). 



t Comptes Rendus, cli. (1910) pp. 734-6. + Tom. cit., pp. 829-31. 



§ Amer. Nat., xliv. (1910) pp. 673-92. 



