64 
tion of a very large material of Danish species of the genus Mysis Latr. (sens. Sars in 
1879), and of Macropsis Slabberi (v. Ben.), as well as of a number of specimens of Gastro- 
saccus Norm. -—~ all shallow water species, — gave a negative result, neither did I find any 
parasite on numerous specimens of a species of Mysidee taken in shallow water in the West- 
Indies, nor on a great number of specimens belonging to two pelagic species of the genus 
Siriella Dana. In Cumacea I haye found altogether five species of the genus Spheronella 
on six species belonging to the genera Diastylis Say, Eudorella Norm. and Iphinoé Sp. 
Bate, which three genera belong each to one of the eight families established by G. O. Sars, 
whereas an investigation of numerous other species, among which a very large material of 
several species which were taken in Denmark in very considerable quantity, as Couna scor- 
pioides (Mont.), Lamprops fasciata G. O. Sars, Leucon nasicus Kr. Leucon nasicotdes Lilljbg., 
Leucon acutirostris G. O. Sars, Hudorellopsis deformis (Kr.) Diastylis resima (Ky.) and 
Leptostylis ampullacea (Lilljbg.j, gave a negative result. Within the order Isopoda, these 

parasites — altogether three species of the genus Sphewvonella — are only found in two 
species of the genus Janira Leach and in Munnopsis typica M. Sars, all three forms 
belonging to the large tribe Asellota, whereas an investigation of numerous forms belonging 
to other families, among which some species of Idothea F., Astacilla Cordiner, and Gnathia 
Leach, were represented by a great number of specimens, gave no result. (Of the small 
order Tanaidacea I have examined a good number of specimens from Denmark and numerous 
specimens of several species from Sicily, without finding a single parasite). The chief 
quantity of the parasites, namely twenty-eight species (the genus Sfenothocheres and about 
three quarters of the genus Spheronella), were found on Amphipoda, and within this order 
exclusively on Gammaridea (on twenty-eight species). An inspection of a great number of 
specimens of different species of Caprellidaee and of some specimens of Cyamidze gave no 
result. (Among the material from the »Ingolf« expedition I found in 1895 on an Avygina 
Kr. a species, which will be described in the report on the results of this expedition). Of 
Hyperiidea I have only examined a few species. In giving a short general view of the 
occurrence of the parasites within the Gammaridea-group, I will avail myself of the twenty- 
five families adopted by G. O. Sars in his new important work: »An Account of the Cru- 
stacea of Norway, Vol. I, Amphipoda«; they are found in one or more representatives of 
the following fourteen families: Pontoporeiide (the genera Bathyporeia Lindstr. and Argissa 
Boeck), Ampeliscid (the genus Ampelisca Kr.), Amphilochidz (the genera Astyra Boeck, 
Amphilochoides G. O. Sars and Gitanopsis G. O. Sars), Stenothoide (the genera Stenothoé Dana 
and Metopa Boeck), Oediceride (the genus Perioculodes G. O. Sars), Paramphithoide (the genus 
Paramphithoé Bruz.), Epimeride (the genus Acanthozone Boeck), Syrrhoidx (the genus Bruzelia 
Boeck), Calliopiide (the genus Calliopius Lilljbg.), Atylidee (the genus Paratylus G. O. Sars), 
Gammarid (the genus Cheirocratus Norm.), Photide (the genera Lemboides Stebb., Protomedeia 
Kr., Leptocheirus Zadd., Gammaropsis Lilljbg. and Microprotopus Norm.), Corophiid (the genus 
Corophium Latr.) and Dulichiide (the genus Dulichia Ky.). Of the remaining eleven families the 
