ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 645 



in any stage of development. Immediately after the conclusion of the 

 second eight-legged resting-stage, the female is ready for impregnation. 



e. 



Crustacea. 



Experiments on Regeneration.* — H. Przibram has previously shown 

 that regeneration occurs in Palsemon when appendages are cut off distal 

 to the " preformed breakage-line " ; he now shows that this is true when 

 the cut is proximal to that line. Antennae, antennules, caudal pieces, 

 may be regenerated after complete excision ; the regenerated antennule 

 had an ear-sac, the caudal piece (of Mysis) an otocyst, and even the 

 telson was re-grown in Palsemon and Mysis. 



Appendages like walking-legs may (in Portunus, Porcellana, Sicyonia, 

 &c.) replace maxillipedes, if the extirpation is proximal to the preformed 

 breakage-line. But in these so-called " Eichard's monstrosities," which 

 Eichard found in nature, the normal maxillipede form is restored after 

 the third moult. They are stages in regeneration, not heteromorpboses. 



In Alphseus, the removal of the larger Schnalzschere is followed by 

 a change in its smaller vis-a-vis, the Zwickschere, which after several 

 moults becomes a Schnalzschere ! The appendage replacing the lost 

 Schnalzschere is a Zioickschere. If the smaller one is removed, it is 

 replaced by another of the same kind ; if both are removed, they are 

 both re-grown in their characteristic forms, but of equal size. 



Variation in Fiddler Crab.f — E. M. Yerkes gives the "place- 

 modes " for twelve measurements on the carapace and extremities of 

 right- and left-handed specimens of Gelasimus pugilator. The means 

 of this table of " place-modes " show that the right-handed animals are 

 larger and less variable than the left-handed. Eight- and left-handed 

 animals occur in approximately equal numbers. Two " stages " appear 

 to be represented by the individuals measured. Many of the curves are 

 compound, and it is probable that in these one mode represents those 

 individuals which have recently moulted, the other those which are 

 almost ready for the process. All the measurements are larger on the 

 side of the great chela. " The results of this study in variation seem 

 to indicate that right- and left-handedness is not directly due to heredity, 

 but is caused by certain slight variations which give one side of the 

 body an advantage over the other." 



Malacostraca from Mediterranean.! — A. O. Walker describes some 

 very striking results obtained by dredging off Cannes and Hyeres, with 

 a modified tow-net to which a stone was attached. Six excursions gave 

 seventy-eight species, including five new species and two new records 

 for the Mediterranean. Among the Schizopoda a form, doubtfully de- 

 scribed as Mysidopsis serraticauda sp. n., but probably the type of a 

 new genus, was found. Among Isopods a form described as Hyssura 

 spinicauda sp. n. was taken, remarkable because the only species of the 

 genus previously described was found in the North Atlantic at a depth 

 of 1450 fathoms. The Munnidae included a single female of Pleurocope 



* Arch. Entwickmecli., r.i. (1901) pp. 321-45 (4 pis.). See Zool. Centralbl., viii. 

 (1901) pp. 619-21. 



+ Proc. Amer. Acad., xxxvi. (1901) pp. 417-42 (3 figs, and 5 tables). 

 % Journ Linn. Soc. (Zool.), xlv. (1901) pp. 290-306 (1 pi.). 



Dec. 18th, 100 J 2 x 



