1909] Torrey: The Leptomeduscu <>/' tin San Diego Region. 27 



folded into four prominent frilled Lobes about a large mouth. 

 Tentacles 150 to 180. Statoeysts small, 1 (or 2) between adja- 

 cent tentacles, about 200 in all. Gonads narrow vertical bands 

 along half the length of each radial canal from the margin. 

 Gonads, canals and manubrium faint yellow; bulbs of tentacles 

 brick-red. 



Diameter of umbrella 15 to 20 mm. 



Distribution. — At the surface in the vicinity of San Diego, 

 during June and July. Ace. Nos. 77. 962, 966, 1379, 1382. 



Fig. 11. — Irene mollis. X 3. 



.This species is easily mistaken at first glance for Eutimalphes 

 hrownei, with which it occurs, but is less robust. It resembles 

 in general /. eoerulea Agassiz, from which it may be distin- 

 guished at once by the position of the gonads. Further, the 

 gastric peduncle is not so tapering, the tentacles are more nu- 

 merous, and the diameter is less than in the eastern species. 



Fam. Aequoreidak Eschscholtz, 1829. 

 Leptomedusae with numerous closed statoeysts and numerous 

 radial canals which bear the linear gonads; manubrium with 

 broad base and thin walls. 



Cen. Aequorea Per. & Les., 1809. 



With the characters of the family. 



Browne (1904) and Maas (1905) rely upon the form of the 

 manubrium to distinguish between Aequorea and Mesonema. 

 My observations on the living Mesonema coerulescens Brandt in 

 the Northern Pacific confirm those of Clans (1883), and T agree 

 with him that this character is of no practical value. 



