264 PROCEEDINGS OF THE NATIONAL MUSEUM. vol.39. 



Bomolochus solesR, taken from the nostrils of the cod common upon 

 the coasts of the British Isles. 



These specimens also included both sexes and proved of great 

 value in a comparison of the mouth-parts. The male of this species 

 has never been described, but Doctor Scott has generously given the 

 author permission to include it in the present paper. In private 

 correspondence he has also furnished many notes and suggestions 

 upon the mouth-parts of the genus Bomolochus, which have proved 

 exceedingly helpful in coordinating the accounts of different authors, 

 in the effort to establish an accurate and common basis for future use. 



This is the smallest of all the families of parasitic copepods, both 

 in number of species and in bodily size. 



As here constituted it contains ten genera, three of which are new 

 to science, while a fourth, Tucca, has been so changed by the dis- 

 covery of its mouth-parts and swimming legs as to make of it virtually 

 a new genus. Hesse has described four other genera which in all 

 probability belong to this family. Two of them, Megabradiinus and 

 Macrohracliinus , would fall in the subfamily Ergasilinae, since the 

 second antennae are developed into long and powerful prehensile 

 organs like those of Ergasilus. The other two, 3Ietopocatacoteinus 

 and Meto])onana'phrissontes, as evidently belong to the Bomolochinse 

 from the structure of the first antennae and the mouth-parts. But 

 Hesse's figures and descriptions are so full of flat contradictions and 

 palpable errors as to render it impossible to locate these genera with 

 any certainty, and hence they must be left until future investigation 

 shall furnish the necessary data. For the good of systematic zoology 

 it is to be hoped that at least the last two names may prove to be 

 synonyms; there is no chance that they were preoccupied. 



The family separates naturally into three groups or subfamilies, 

 which differ in habits as well as morphology, and thus constitute well- 

 marked divisions. (See key, p. 311.) 



The first of these subfamilies, the Ergasilinae, are typically fresh- 

 water forms, and nearly all the species are found upon the gill fila- 

 ments of fresh-water fishes. The second subfamily, the Bomolo- 

 chinae, are as typically salt-water forms, and no one of them, so far 

 as known, has ever been found in fresh water. The third subfamily, 

 the Taeniacanthinae, are also salt-water forms, and none of them 

 have thus far been found upon fresh-water fishes. 



There are one or tv/o species (Artacolax cornutus, Irodes tetrodontis, 

 etc.) that reach a length of 3 or 4 mm., but all the remaining species 

 are much smaller, and many of them are under 1 mm. in length. 

 The Ergasilidae thus compare more closely in size with the free-swim- 

 ming forms than do any of the other parasitic copepods. This 

 resemblance is increased by the fact that the eggs are multiseriate 

 and are carried in elliptical or pear-shaped pouches almost exactly 

 like those of Ctjcloys and other free-swimmers. 



