414 



SUMMARY OF CURRENT RESEARCHES RELATING TO 



The palps of masticating insects, female Araneidre, and Chilopod 

 Myriopoda, represent degenerate appendages, without definite function, 

 all hut useless, and readily dispensed with. The same may he said of 

 many of the palpi form organs of Crustaceans, since Isopods and Amphi- 

 pods, deprived of the endopodites of their maxillipedes, seem to get on 

 just as well. Finally, the exopodites (miscalled palps) of the maxilli- 

 pedes of Decapod Crustaceans do not share at all in the prehension of 

 food or in its introduction into the mouth. 



Abbreviated Metamorphosis of Alpheus, and its Relation to the 

 Condition of Life.* — Mr. F. H. Herrick has discovered a Bahaman 

 species of Alpheus (A. prsecox sp. u.) in which the animal acquires 

 all its adult characters in twenty-four hours after hatching. Some 

 interesting data are afforded hy the subjoined table : — 



It is now generally agreed that the zoea of Decapod Crustaceans is 

 not a primitive form, but one gradually acquired as the habits of the 

 larva diverged from those of the adult. "When, therefore, the habits of 

 the adult or larva tended to converge, the zoeal stage would be shifted 

 to the egg. The fact that of the numerous species of Alpheus only two 

 are known to undergo an abbreviated development is evidence of the 

 extreme plasticity of young animals, and of their tendency to vary with 

 varying conditions of life. 



Reproduction of Lost Parts.f — Mr. G. Brook gives an account of 

 his observations on the reproduction of lost parts in the common lobster. 

 A brief resume of the history of previous observations is given. The 

 reproduction of the chelae, walking legs, and antennae is described, and 

 their rates of growth are noted. It seems probable tliat limbs lost in 

 summer are reproduced more rapidly than those lost in winter. The 

 author describes the deposition of pigment in the new appendages, and 

 notices finally, in regard to the rupture of the carapace during ecdysis, 

 that the cephalothorax splits along the dorsal suture in some cases, but 

 certainly does not do so in others. 



Parasitic Castration in the Eucyphotes of Palaemon and Hip- 

 polyte.J— M. A. Giard has recently collected evidence which supports his 

 view that male Palsemons appear not to harbour Bopyri, because the 

 atrophy of the testes in the infected males produces, as a consequence, an 

 arrest of the external sexual characters. Reference is made to the 

 secondary sexual characters in Palaemon, indicated by Grobben and 



* Johns-Hopkins Univ. Circ., vii. (1888) pp. 34-5. 



t Proc. R. Phys Soc. Edin., ix. (1887) pp. 370-85 (1 pi.). 



j Comptes Rendus, cvi. (1888) pp. 502-5. 



