152 THE MEDUSAE. 



as is seen in side view (PI. 39, fig. Jt). As the genital folds grow larger and 

 larger they gradually obscure the diverticula of the canals (PI. 39, fig. 3) 

 until finally it appears as though the latter were merely wavy in outline, 

 as Browne (: 02) has described them for P. antarctica. This structure of the 

 canals and gonads is similar to that found in P. longigona by Maas, who 

 states that the canals " sind an und fur sich einfach und zeigen Ausbuchtungen 

 nicht selbstandig, sondern nur in Zusammenhang mit Gonaden entwickelt " 

 ('93, p. 66). The gonads extend for nearly the entire length of the canals, 

 but do not quite reach their distal extremities. 



Color. — The color of this species is one of its most striking characters. 

 The basal parts of radial canals and manubrium as well as the tentacular bulbs 

 are of a very brilliant opaque brick-red ; while gonads, distal portions of the 

 canal system, and extremities of the tentacles are of a paler shade of the 

 same color. Along the central line of each radial canal is a pale band, 

 these four bands forming a cross on the base of the stomach (PI. 39, fig. 7). 

 The pigmentation is both ectodermic and endoderraic. The endoderm cells 

 contain masses of red, yellow, and black pigment spherules of large size, 

 while the ectoderm cells in the pigmented regions are crowded with 

 minute red granules. 



Ptijchogena erythrogonon is evidently an intermediate form. So far as 

 the present collection illustrates its range, it appears to be confined to the 

 Humboldt Current, in the neighborhood of the Peruvian coast. Of the three 

 other members of the genus, one, P. antartica, is from the Antarctic ; two, 

 P. lactea and P. longigona, from the north Atlantic. P. lactea is probably a 

 surface form ; P. longigona is almost certainly from the intermediate waters, 

 while we have as yet no data as to the bathy metric occurrence of P. antarctica. 



Eucopidae Gegenbatir, 1856. 



Leptomedusae with closed otocysts; with four, six, or eight radial 

 canals; with gonads lying along the canals; with well-developed barrel- 

 shaped manubrium. 



Only one of the four subfamilies of Eucopidae proposed by Haeckel, 

 (79) the Eutiminae (Maas, : 05), has stood the test of time. This sub- 

 family, including forms with a long peduncle and with only eight oto- 

 cysts, seems sufficiently well characterized. The other subfamily with a 

 peduncle, Eireninae (Haeckel), with more than eight otocysts, must be 



