CYDIPPID.E. 29 



flappers. The pigment-spots become sm<aller and less conspicuous with 

 advancing age. 



This species is exceedingly common in Eastport harbor, during the 

 month of September. 



Arctic Ocean (Mertens, Scoresby) ; Baffin's Bay (Fabricius) ; Massa- 

 chusetts Bay, and Eastport, Me. (A. Agassiz). 



Museum diagram No. 3 after Alex. Agassiz. 



Family CYDIPPIDiE Gegenb. [rest Ag.) 



Cydlpp'uke Gegexb. Archlv f. Nat., 18jG, 1. p. lOG. 

 Callianiridce Escn. {p. p.) Syst. d. Aral., p. 21. 1829. 

 CydippidcB Agass. Cont. Nat. Hist. U. S., III. p. 2'J3. 18G0. 



PLEUROBRACHIA Flem. 



Pleurohrachia Flem. Phil. Zool, II. p. 612. 

 Cydippe Escii. Syst. dcr Acal., p. 29. 1829. 

 Cydippe Less. Zooph. Acal., p. 104. 1843. 

 Pleurohrachia Agass. Mem. Am. Acad., IV. 1849, p. 314. 

 Pleurohrachia Agass. Cont. Nat. Hist. U. S., III. p. 203. 1860. 



Fif:^. 36. Still furtlior advanced Mertensia, seen from the broad side. 



Fig. 37. Young Mertensia about in the same condition as that of the preceding figure, seen 

 from the narrow side. The main branches of the ambulacra! system have lost the character of 

 pouches. 



