386 



MEMOIKS OF THE NATIONAL ACADEMY OF SCIENCES. 



lu Nos. 1 to 4 we find little variation from tbe hrevicarpus form, which we consider as nearest 

 to the type of the species. From No. 5 to No. 15 the departure from this type is increasingly 

 evident, and in Nos. 12 to 15 we recognize the widest divergence in the varity longicarpus. 



No. 5 is an interesting case, since it combines the characters of both varieties. The aural 

 spine is rather blunt and extends to one third the length of the second segment of the antcnular stalk. 

 The inferior basal spine is rather less than one-half the length of squamous spine ; upper basal spine 

 a rudimentary knob. The squamous spine has a well-developed squame; nearly equals length 

 of antennal peduncle. The "finger" and "thumb" of small chela end in simple, sharply pointed 

 hooks. There is an inconspicuous tuft of setie on the dactyle. The carpus is long. (See Table 11.) 



No. 8 is also an interesting variation. The anteunie are intermediate in character, between 

 the extremes of the table, while the small chela is of the hrcvicarptis type. There is a rudimentary 

 antennal scale. The tips of the small chela are simple. There is no tuft, and the carpus is short. 



In No. 9, which is of the same sex, the same length, anil from the same locality as No. 8, the 

 small chela has the characters of the variety longicarpus. Nos. 5 to 12, in the middle of the table, 

 show in one way or another intermediate characters between the extremes, Nos. 1 to 4 and Nos. 

 12 to 15. 



TI. — MEASUEEMENTS IN MLLLEttETERS. 



Table ii. 



[Locality: Nassau, N, P., Bahama Islands.] 



