60 U.S. NATIONAL MUSEUM BULLETIN 23 6 



In the shape of the legs and the presence of the seta on the basis 

 there is complete conformity. Yamaguti does not mention the scale- 

 shaped teeth, but these are obscured easily in a dissection. On leg 5, 

 though it has almost the same shape and is composed of 1 free seg- 

 ment, Yamaguti figures 2 setae. The above-mentioned endopodal 

 setae, as well as the seta on the basis, are chitinized very weakly and 

 during dissection easUy fold under the thick segments. The missing 

 seta on leg 2 may have been removed during preparation. The 

 above-mentioned particulars would certainly not suflBice to separate 

 two forms specifically if they were living on the same host. 



The Ifaluk specimen was secured from the alga Microdictyon, 

 apparently by washing, and originally it must have been attached to 

 (the gills of) a fish. The species of fish, Leptoscarus japonicus, from 

 which Bomolochus leptoscari was recorded originally, is restricted in 

 its distribution to the immediate neighborhood of Japan, but several 

 species of the genus and several closely allied genera are distributed 

 widely over the southeastern Pacific and, though the fact has never 

 been proved, it seems likely that B. leptoscari also occurs on the 

 relatives of L. japonicus and thus covers a greater part of the Pacific 

 than the Japanese record suggests. I have inspected the two speci- 

 mens of L. japonicus in the collections of the Rijksmuseum van 

 Natuiu'Hjke Historic but have failed to find a parasite. During a 

 study of the literature on Bomolochus when identifying my specimen, 

 I have gained the impression that some of its species are somewhat 

 loosely founded, the specificity of the host being the decisive character. 

 A revision of more material will probably show that, for some species 

 at least, a variety of hosts is available or will probably show that 

 related hosts harbor forms of a certain parasite. Unfortunately, 

 important taxonomic details (development of the antennular 

 setation, structure of antennae and maxillipedes, setation of the legs) 

 are omitted often from descriptions of new species or, when given, 

 appear to be of a very doubtful standard. Only recently have some 

 species been adequately described (Stock, 1953; Shiino, 1957), but 

 even such a fairly well-known form as Bomolochus hellones Burmeister 

 is still known from its original figm-e which, with the inadequate and 

 faulty information taken from this old drawing, is reintroduced over 

 and over again in scientific literature. In this genus, in particular, 

 careful redescriptions of well-known forms, preferably from tj^pe 

 hosts, are needed more than the inadequate introduction of new forms. 



Bomolochus leptoscari originally was recorded from Hamajima in 

 the Mie prefecture of Japan (one 9 specimen, 1.15 mm., from Lepto- 

 scarus japonicus Cuvier and Valenciennes). The present specimen, 

 again a 9, was taken from the lagoon off Paugob Canoe House on 

 Falarik Islet in the Ifaluk Atoll at a depth of 35-40 feet. 



