12 University of California Publications in Zoology. [Vol. 6 



Melicertum proboscidifer Mans, may be identical with a Thau- 

 mantiid in the collection of the U. S. S. Albatross in 1904 on the 

 California coast, to be considered in a later paper. The Alba- 

 tross collected at the same time three species described in the 

 present paper as Scrippsia pacifica, In ru mollis and Tiaropsis 

 (Tiaropsidium) kelseyi, extending the range of the latter to 

 Monterey, California. The type specimens of A. coerulesci us 

 (Brandt, 1838) were collected by Mertens in 1827, about 1600 

 miles west of San Diego. Brandt's paper describing and figur- 

 ing Mertens' collections completes the list of papers dealing with 

 Pacific Coast Leptomedusae. 



Among the latter, those of the San Diego region form at 

 present a well isolated group, whose relationships to other groups 

 will be discussed later in connection with the other medusae of 

 the region. Following is the list of species arranged by families: 

 Thaumantiidae Ptychogena californica, n. sp. 

 Polyorchidae Scrippsia pacifica, n. gen., n. sp. 

 Mitrocomidae Mitrocoma discoidea, n. sp. 



Tiaropsis (Tiaropsidium) kelseyi, n. subgen.. 

 n. sp. 

 Eucopidae Obelia purpurea, n. sp. 



Phialium baJceri, n. sp. 



Phialidium lomae, n. sp. 



Phialopsis diegensis, n. gen., n. sp. 



Eutimalphes broumei, n. sp. 



In ui mollis, n. sp. 

 Aequoreidae Aequorea coerulescens (Brandt). 



The hydroids for none of these species are definitely known. 



LEPTOMEDUSAE Haeckel, 1866. 

 Craspedote medusae with gonads on radial canals, sense or- 

 gans usually velar statocysts, in some forms ocelli and sensory 

 clubs or cordyli. Non-sexual generation calyptoblastic hydroids. 



Fam. Tiiaumantiidae Gegenbaur, 1856. 

 Leptomedusae without statocysts; with numerous tentacles, 

 usually bearing ocelli on their bases, cordyli (sensory clubs) be- 

 tween them ; radial canals unbranched. 



