FISHERY BULLETIN: VOL. 73, NO. 1 



albatrossi. I have examined 15 S. major from 

 three of Tattersall's collections. Two of the col- 

 lections (USNM 82439—2 S. major, and USNM 

 81268—10 S. major) contained the holotype 

 and paratype respectively of T. albatrossi. In 

 the third collection (USNM 82440— three S. 

 major; Albatross stn. 4861; lat. 36°19'N, long. 

 129°47'E; 163 fathoms; 31 July 1906) I found a 

 female S. major bearing four scars from an 

 ellobiopsid. 



Effect on the Host 



The mysid specimens bearing the type and 

 paratype ellobiopsids were females of mature 

 size but vidth reduced oostegites. This apparent 

 sterilization agrees with observations of Page 

 (1941), Einarsson (1945), and Nouvel (1941), 

 who noted that ellobiopsids sterilize their hosts. 

 A scarred mature female S. major in USNM 

 82440 was brooding young but appeared to have 

 been parasitized earlier by an ellobiopsid. The 

 scars consisted of holes in the carapace, probably 

 caused by the primary stalks of the parasite. 

 Each of the four holes had a heavy deposit of 

 pigment at the margin that was surrounded by 

 a clear area. Thus, it appears that the steriliza- 

 tion by ellobiopsids may be temporary, as sug- 

 gested by Wickstead (1963), or it may be in- 

 fluenced by the age of the host at the time of 

 infection. 



Distribution 



The new species has been reported only from 

 the eastern coast of Korea, the type locality of 

 the parasite and its host. 



Derivation of Name 



The specific name albatrossi is selected to honor 

 the U.S. steamer A /6a^ross, the vessel from which 

 the parasitized mysids were collected. The many 

 biological collections made from the Albatross 

 during 39 yr of service to the U.S. Fisheries 

 Commission and later to the U.S. Bureau of 

 Fisheries have been of immeasurable value in 

 the investigation of life in the oceans. 



Thalassomyces fasciatus (Fage 1936) 



Amallocystis fasciatus — Pequegnat (1965). 

 Thalassomyces fasciatus — Vader (1973b). 



Thalassomyces fasciatus is a large species 

 known to parasitize only lophogastrid mysids of 

 the genus Gnathophausia. Pequegnat (1965) 

 found it on G. ingens (Dohrn) and G. gracilis 

 Willemoes-Suhm off central Baja California. It 

 has also been collected in the Santa Cruz Basin 

 off California (S.B. Collard, Marine Environ- 

 mental Sciences Consortium, Dauphin Island, 

 AL 36528, pers. commun.). Boschma (1959) re- 

 corded this ellobiopsid on G. gigas Willemoes- 

 Suhm from Spain; on G. ingens from Morocco, 

 the Lesser Antilles, and the Maldive Islands; 

 and on G. zoea Willemoes-Suhm from Portugal, 

 Guiana, the Fiji Islands, and New Zealand. 



Thalassomyces fasciatus attaches to the ventral 

 surface of the first abdominal somite of the host. 

 The gonomeres are oval and about twice as long 

 as wide (0.4 by 0.2 mm), and normally, there 

 is only one gonomere per trophomere (Boschma 

 1959). The trophomeres are long (1.5 mm total 

 length) and joined in groups of five or six to 

 the primary stalk (Fage 1941). In these aspects 

 T. fasciatus differs from the T. albatrossi n.sp. 

 found on S. major by Tattersall (1951), which 

 were erroneously believed to be T. fasciatus by 

 Boschma (1959) and Collard (1966). The size of 

 the gonomeres and total length of trophomeres 

 (including the gonomeres) in the two species are 

 similar, although my specimens of T. albatrossi 

 have a greater number of gonomeres per tropho- 

 mere than T. fasciatus and therefore do not appear 

 to be as long and pendulate. 



ADDITIONAL RECORDS OF 

 NORTH PACIFIC ELLOBIOPSIDS 



Besides the three species of Thalassomyces 

 found on mysids, seven other ellobiopsids have 

 been found on crustaceans in the North Pacific. 

 The following sections summarize current know- 

 ledge about the hosts and distribution of these 

 seven ellobiopsids. 



Thalassomyces marsupii Kane 1964 



Thalassomyces marsupii— Gait and Whisler 

 (1970), Vader (1973b). 



Thalassomyces marsupii is found inside the 

 marsupium of host amphipods. The mature para- 

 sites resemble compact egg masses. Usually the 

 whitish spherical gonomeres are smaller than the 



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