370 SUMMARY OF CURRENT RESEARCHES RELATING TO 



rapidly. The Zostera areas are noteworthy for the abundance of Rissoa 

 and shnilar small Gastropods, which are of some importance as fish-food, 

 besides being devoured by crabs and starfishes. In addition there are 

 Gammarids, Isopods, Mysids, a few bivalves, and Polychsets. The 

 author has some suggestions to make in regard to the utilization of 

 Zostera and the improvement of the feeding-grounds of fishes. 



J. A.T 



rood of Post-larval Fishes. — Marie Y. Lebour {Joimi. Marine 

 Biol. Assoc, 1918, 11, 483-69, 7 figs.). It now seems a well-established 

 fact that the majority of young fish eat the small animals from the 

 plankton more than the diatoms and other unicellular organisms, except 

 in the cases of some of the very young fishes which have been found to 

 eat diatoms before taking to animal food, and in the few exceptional 

 cases of fish which are true vegetarians. Miss Lebour's investigation 

 deals with about fifty species. There is evidence of a certain amount of 

 selection of food. Fish with the smallest mouths eat the smallest forms, 

 both large and small being eaten by those with large mouths. Ento- 

 mostraca form the greater part of the food, and the commonest in order 

 of frequency is the Cladoceran Podon (probably inter medms), and the 

 Copepods Fseudocalanus elongatus, Temora longicornis, and Euterpina 

 acutifrons in the proportion of 6:4:3:2. Cirripede larvae and small 

 ova are also common ; Diatoms and Peridinids are mostly inside the 

 Copepods. J. A. T. 



Disappearance of Conus arteriosus in Teleosts. — Wilbur C. 

 Smith (Anat. Record, 1918, 15, 65-71, 16 figs.). The conus arteriosus 

 is characteristic of Elasmobranchs and Dipnoi. It is present only in a 

 few Teleosts. Its gradual disappearance can be illustrated in a series of 

 types. In most cases it has been lost by intussusception or recession 

 into the ventricle, as Hoyer has maintained. In a limited number of 

 cases this is not the case ; the conus is taken up by the caudal elonga- 

 tion of the bulbus arteriosus. J. A. T. 



Note upon the large Mononuclear Leucocytes of the Peripheral 

 Blood and the Macrophages at the Site of Injury amongst the 

 Wounded.— A. Nanta {C.R. Soc. Biol., 1918, 81, 256-9). In a 

 previous note Nanta showed that tissues around a wound are rapidly 

 infiltrated with leucocytes, chiefly macrophages ; whilst in the peripheral 

 blood a leucocytosis of 30 to 60,000 occurs rapidly, the differential 

 count showing 80-85 polynuclears and 5-15 mononuclears per cent. 

 In further investigating the role of the mononuclear leucocyte, Nanta 

 ol)served that the most severe and the most extensive wounds — but not 

 necessarily the most severe hsemori hages — were attended by the highest 

 mononuclear leucocytosis. Some of the mononuclears of the blood are 

 normal, but the majority are abnormal and show considerable increase 

 in strongly basophile protoplasm, and are often rich in irregular azuro- 

 phile granules, witli fissured nuclei, similar to those associated with 

 diseases of the spleen. Smear preparations from the spleen show the 

 presence of these cells in large numbers in the Malpighian corpuscles. 



