ECONOMIC RELATIONS, ANATOMY, AND LIFE HISTORY OF GENUS LERN^A. 17I 



Cunnington stated: "So far as I am aware, the existence of the genus in Africa 

 has never been put on record before" (191 4, p. 819). 



But barnimii was captured in i860 at Dabbeh on the River Nile in Nubia. The 

 single South American species is probably not a fair representation of the genus on that 

 continent, but simply means that there has not been very much search for these 

 parasites upon South American fishes. 



Similarly, the nonappearance of Asia in the above list must not be interpreted as 

 excluding the genus from that continent. Practically none of the fresh-water fishes 

 belonging to that region has ever been examined for parasites, and there is no obvious 

 reason why the genus should not be represented there as well as elsewhere. 



Hosts. — This entire genus and the single known species of the genus Sylvestria 

 are the only Lemasans which infest fresh-water fishes, but they are widely distributed 

 amongst the different families of fishes, as can be seen from the table which follows. 



Moreover, it will be noted that if the larvae thus far discovered can be taken as 

 typical of the entire genus, every species of Lerncea has at least two hosts, widely differ- 

 ing from each other. One of these serves as the temporary host of the copepodid 

 larvae, the other as the final or permanent host of the adult female. Our knowledge of 

 the larvae of the different species is at present too limited to enable us to draw any 

 general conclusions with reference to the relations between the temporary and perma- 

 nent hosts. But it is worthy of comment that both kinds of hosts include fish which 

 frequent the surface, others which frequent the bottom, and a third class which may 

 be found at almost any depth. 



Probably later investigation will discover some general relation between these; 

 it would at least seem reasonable that the two hosts of the same species should be fishes 

 that frequent similar localities. 



Host species. Parasite species. 



AmblopUtes rupestris (redeye) criiciaia, adult female. 



. • t , /u 111, »j\ fior<«a, adult female. 



Ameturus nebulosus (bullnead) i 



\pomotidis, copepodid larvee. 



Aplodinoitis grunniens (sheepshead) tenuis, adult female. 



Barbus bynni (fish of River Nile) temnocephala, adult female. 



Caiosiomus nigricans (hog sucker) tortua, adult female. 



Clarias mossambicus (fish of River Nile) diceracephala, adult female. 



Cyprinus carassius (carp) cyprinacea, adult female. 



£.ox iactW (pike) rcy/>rmac.a, adult female. 



\esocina, adult female. 



Eupomotis gibbosus (sunfish) cruciata, adult female. 



Gasterosteus aculeatiis (stickleback) esocina, adult female. 



Labeo niloticus (fish of River Nile) barnimii, adult female. 



{variabilis, adult female. 

 dolabrodes, adult female. 

 pomoiidis, adult female. 



Lepisosieiis platostomus (short-nosed gar) variabilis, copepodid larvae. 



Lota vulgaris (burbot) esocina, adult female. 



Micropterus salmoides (largemouth black bass) (cruciata, adult female. 



\anomala, adult female. 



Moxostoma macrokpidotum (large-scaled sucker) (cruciata, adult female. 



(catostomi, adult female. 



Notropis cornuius (shiner) pectoralis, adult female. 



Perca fluviatilis (perch) esocina, adult female. 



Phoxinus marsilii (minnow) phoxinacea, adult female. 



Polypterus birchir (fish of the White Nile) haplocephala, adult female. 



