538 



MERISTIC VARIATION. 



[part I. 



Fig. 196. Proximal parts of the right 



nurus vulgaris, No. 828. 



Ill, extra 



C. Antennce. 



*828. Palinurus vulgaris : right antenna bore three complete 



filaments. So far as last spiny joint (merocerite) normal. Of 



this joint the peripheral portion 



much enlarged, presenting two 



articulations. The most posterior 



bore a normal carpocerite and fila- 

 ment (Fig. 196, 1). The anterior 



articulation bore a double carpo- 

 cerite with two filaments (II and 



III). As author points out, II is 



structurally a left antenna. [By 



the kindness of M.Alphonse Milne 



Edwards I have been allowed to 



examine this specimen. I am not 



sure that I succeeded in correctly 



determining the surfaces of the 



extra antennae, for the basal parts 



were not very fully formed ; but 



according to my determination 



their relations differed markedly 



from those of any of the Schematic antenna^of >S 



positions, for while the position I, the normal. II, extra left 



of origin is V VA the two extra ri 8 nt - ( After Leger.) 



antennas stand very nearly in the Position DA.] L£ger, Ann 



sci. nat., Zool, 1886, S. 7, I. p. 109, PL 6. 

 *829. Astacus fluviatilis : exopodite of left 



antenna(Fig. 197)bears two supernumerary 



points, R' and L', which seem to have been 



inserted upon the internal border of the 



normal exopodite. Stamati, G., Bull. Soc. 



Zool. France, 1888, xm. p. 199, Jig. 



Amorphous Cases. 



As has been stated, there are many cases, 



recorded or preserved, in which the nature of 



the parts cannot be made out. The majority 



of these are, I believe, injured or deformed 



limbs, and not cases of repetition of parts. 



Nevertheless of the latter class there are un- tilis having extra points to 



t , , ,. , „ , , exopodite ol left antenna. R, 



doubtedly some amorphous cases, though they normal right. L, normal left. 



are far less common than regular ones, even R', L', extra right and left. 



as normal structures are more common in their (After Stamati.) 



regular shapes than in a deformed state. I mention the following as 



being, I think, the earliest record of abnormalities of this class. 



830. Homarus : left chela having irregular process on inner border of 



dactylopodite, and two irregular processes on inner border of index. 



[No description.] Bernhardus a Berniz, Miscell. Curios., Jena, n. 



1671, p. 175, Obs. ci. PI. 



MBfcflll ■ 



Fig. 197. 



Astacus fluvia- 



