182 SUMMARY OF CURRENT RESEARCHES RELATING TO 



Amhlyomma hehrseum and Hyalomma segyptiiim. regeneration takes place 

 equally well after operations on larv^and nymphs, and perfect regenera- 

 tion of hypostome, palps and digits occurred after most amputations. 

 When freshly gorged larvte of Argas persicus had their legs amputated, 

 the corresponding limbs were not regenerated in the first nymphal 

 stage, but when these nymphs were fed and allowed to undergo a further 

 moult without operative interference, they regenerated these mutilated 

 limbs perfectly. When first-stage nymphs, under like conditions, were 

 similarly mutilated, they gave rise to second-stage nymphs with well- 

 formed legs of subnormal size. Leg amputations in Amhlyomma and 

 Hyalomma were followed in all cases by regeneration. The regeneration 

 of mouth parts is important in immature ticks, because in nature they 

 are frequently injured through their forcible removal from the host, the 

 hooked hypostome and digits of the chelicerse being particularly liable 

 to breakage, especially in Ixodid ticks. J. A. T. 



Habits of Argas reflexus. — R. Lienhart and P. Remy {Gomptes 

 Rendus Soc. Biol. 1920, 83, 1155-6). Living adults were found 

 at the University of Nancy in a dove-cot vacated since 1914. They 

 must have been fasting all that time, for the dove-cot was quite closed. 



J.A. T. 



S. Crustacea. 



Heart of Euphausid. — G. Colosi {Atti R. Accad. Sci. Torino, ]920, 

 55, 51-62, 4 figs.). A histological study of the heart of Nematoscelis 

 megalops Gr. 0. Sars. The cardiac wall shows an external, connective- 

 tissue, continuous layer, and an internal, muscular, and discontinuous 

 layer. There is no endothelium. The movements of the heart are due 

 to the parietal muscles, and especially to the muscular trabecul^e which 

 cross the cavity in various directions. The contractions are mostly 

 dorso- ventral. The ostial lips are purely muscular. The ostia open 

 and shut by the action of the special muscles which traverse the cardiac 

 cavity. The cardio-arterial valves are purely muscular ; they open and 

 shut according to the pressure of the blood, mainly or perhaps wholly. . 

 The walls of the arteries consist of a homogeneous internal intima and 

 an external connective adventitia. There are no muscle fibres and the 

 arteries are not contractile. The walls of the venous sinuses consist of 

 a homogeneous internal intima and an external connective adventitia. 

 There are no muscle fibres and the sinuses are not contractile. The 

 arterial valves and the ostial lips represent a continuation of the internal 

 muscular envelope of the heart. The walls of the arteries and veins 

 are continuous with the external connective-tissue tunic of the heart. 



J. A. T. 



Development of Calcareous Skeleton in Cirripeds. — Hjalmar 

 Bkoch {VidensTc. Medd. Dansk. Nat. Form, 1920, 72, 83-5). A pre- 

 liminary account of a study of the development of the plates in Mitella 

 {PoUicipes) polymerus. As in Scalpellum the first plates to appear are 

 the five primordial valves (carina, terga and scuta). They appear in the 

 pupa-stage as five chitinous plates of porous structure soon after the 

 pupa fixes. Very soon the calcification begins, and almost at the same 



