ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 



313 



cceca branched over the arteries. In the Palsemonidse, besides the 

 hepatic phagocytes, there are in the heart vacuolar cells which, in a feeble 

 degree, have a phagocytary function. The vacuolar liquid has an acid 

 reaction. 



Minute Structure of Heart in Decapoda.*— W. Gadzikiewicz has 

 studied this in Pahcmon, Pachygra/psus, and Astacus. The heart 

 consists of two layers — an internal muscularis and an external adventitia 

 (visceral pericardium or epicardium). The adventitia consists of vesi- 

 cular cells in many rows, suggesting many-layered epithelium. The 

 myocardium consists of individual fibres whose protoplasmic substance 

 coalesces to form a general protoplasmic matrix in which the contractile 

 fibrils lie. Many blood corpuscles merge in the protoplasmic substance 

 of the muscle-fibres, and are disintegrated. There is no "cardiac 

 endothelium " nor " intima." The author's conclusions support the 

 heemocoel theory of Lang. 



Life-History of G-nathia maxillaris.t — Geoffrey Smith has studied 

 the metamorphosis and life-history of this Gnathiid or Anceid, whose 

 larval form, known as Praniza, lives ecto-parasi tic-ally on various kinds 

 of fishes. He discusses the final metamorphosis of the Praniza into the 

 male and female adult, and the striking variation in the size of the adults. 

 The adult males vary in size from 1-8 mm., and the much rarer adult 

 females from 1-7 mm. The bimodality of the curve of size is due to the 

 existence of two critical periods for the final transformation, and the 

 presumption is strong that the size to which any larva may attain is 

 chiefly due to the conditions of nutrition it meets with, and its fortune 

 in being brushed off its host at an early or late stage of growth. The 

 larger adults owe their size to the length of time spent and the amount 

 of nutrition acquired during the Praniza stage. On the whole the small 

 males have mandibles that are broader and shorter than those of the 

 large males : in other words, there is an incipient structural dimorphism 

 in the mandibles, in correlation with the difference in size of the males. 



The life-history may be thus tabulated : — 



Normal segmented larvae 

 0-8-1-2 mm. 



Praniza? on fish 

 1-4 mm. 



Small adults on ground 



Giant segmented 

 larva3 on ground 

 4-5 mm. — 



Praniza) 



on fish 

 5-8 mm. 



Large adults on ground 



Notes on Alcippe lampas.J — K. W. Genthe gives some notes 

 which are supplementary to the work of Berndt and earlier writers upon 



* Bull. Intermit. Med. Sci. Crncovie, 1904, pp. 424-34 (7 figs.), 

 t MT. Zool. Stat. Neapel. xvi. (1904) pp. 469-71 (1 pi.). 

 : Zool. Jahrb.. xxi. (1904) pp. 181-200 (2 pis.). 



