ORDER PCECILOPODA. 371 



vi. 2 ; Monoculus gyrini, Cuv. Tab. Elem. de I'Hist. Nat des 

 An. p. 454 ; Ozolus gastei'ostei, Lat. ; Hist. Nat. des Crust, 

 et des Insect. IV. xxix. 1 — 7 ; Desm, Consid. L, i. ; Pou du 

 gasteroste, Baker, Micros. II. xxiv.) fixes itself on the under" 

 part of the body of the tadpoles of frogs, of stickle-backs, &c., 

 and sucks their blood. Its body is flatted, of a clear yellowish 

 green, and about two lines and a half in length. The younger 

 Hermann, who has very well described this animal in its per- 

 fect state, and who quotes a manuscript of Leonard Baldaneur, 

 a fisherman of Strasburg, bearing the date of 1666, in which 

 the same animal is figured, says, that it is seldom to be met 

 with in the environs of that city, except on trouts, and that it 

 often causes their death, especially of those which are kept in 

 fish-ponds. It is also found on perch, pikes, and carps. It has 

 never been found upon the gills. Like the gyrini, this animal 

 whirls round like a top. He says that its body is divided into 

 five rings, not very distinct, upon the back. 



Caligus, M?«Z/., 



Have no cupper-feet ; those of the anterior pairs are un- 

 guiculated, the others are divided into a number, more or 

 less considerable, of pinnulae, or in the form of membranaceous 

 leaflets. The testa leaves discovered a good part of the body, 

 which is terminated posteriorly, in the majority, by two long 

 filaments, and in the others by appendages, in the form of a 

 fin or stylet. This interval also frequently presents some 

 other appendages, but small, or much less projecting. 



The name oi Jlsh-Uce, under which they are collectively 

 designated, indicates that their habits are the same as those 

 of the arguli, and the other siphonostomata. Many naturalists 

 have considered the tubular filaments of the posterior extre- 

 mity of their body to be ovaries. I have sometimes discovered 

 eggs under the posterior and branchial feet ; but never in 

 these tubes. Moreover, we never see any exterior oviducts, 



B b 2 



