248 ALLAN HANCOCK PACIFIC EXPEDITIONS VOL. 18 



extends down almost to the end of article 4 and has up to 10 serrations. 

 The eyes of the males are larger in southern specimens. 



These and other differences might be explained on the basis that 

 warmer temperatures allow maturation of postliminious secondary sexual 

 features. 



Specimens from Newport Bay, California 



Diagnosis. — Differing from the typical in (1) the longer distal 

 portion of peraeopod 4, the ratio of the combined lengths of articles 3 

 to 7 compared with the length of article 2 being 15:6 while normally 

 it is 13:6; (2) the ratio of width to length of peraeopod 5, article 2 

 is 47:52, thus being broader than in typical specimens; (3) article 2 

 of peraeopod 5 extends down a little beyond the end of article 4, 

 more than in the typical; (4) the ventral edge of article 2 is truncated 

 while commonly it is strongly convex, thus accounting for the broader 

 appearance of the fifth peraeopods in this form; (5) in gnathopods 1 

 and 2 the ratios of articles 5 and 6 are respectively ; 3 :4 and 2 :3, thus 

 much less than in the normal form; (6) the posterior edge of the third 

 epimeron is more concave than typically, the lower corner being more 

 produced and rounded; (7) the telson is more slender; (8) articles 2, 

 4, 5, 6 of peraeopod 3 have a ratio of width which is 9 :6 :5 :2 compared 

 with 9:7:6:2 in typical specimens; (9) articles 5 and 6 of peraeopod 

 3 have a ratio of length which is 3:4 compared with 1:1 in the 

 typical form. 



Remarks. — This minute facies is a bay form, being restricted as 

 presently known to Newport Bay, California (J. L. Barnard 1959). 

 Apparently it is a reflection of special environmental conditions, perhaps 

 warmer temperatures. However, the phenotypic expressions of the 

 bay form tend away from the trends noted in warm southern oceanic 

 representatives as compared to northern cold water animals (which in 

 a sense are bay forms also). This trend is noted particularly in the 

 fifth articles of the gnathopods which increase from short to long in 

 the following progression: Newport Bay — Puget Sound — southern 

 oceanic. 



The fourth peraeopods of the Newport Bay form are longer than 

 in the other forms, while the third epimera are different. The fifth 

 peraeopods represent the extreme of the tendency of southern animals 

 to have a longer and more truncated second article, but strangely the 

 number of serrations on the posterior edges is fewer than either of 



