NO. 1404. PARASITIC COPEPODS—CALIGIDyl^WILSON. 481 



practically iioiuleg-eneratc, while the Pandarinre are vcr}' evidently 

 degenerate; this g-roup therefore forms a connecting link between 

 the two and enables us to discover and emphasize the initiator}'^ steps 

 in degeneration. 



They thus possess the greatest possible ecological interest, and a care- 

 fid study of their habits and mode of lifi^ can not fail to yield valuable 

 facts and suggestions. 



HISTORICAL. 



The first accounts that can be referred to these genera with any 

 degree of certainty are those of (Tunner (1765), Stroem (1762), and 

 Baster (1765). They describe and figure some parasites which they 

 call fish lice, but evidently they entirely mistook the nature of the ani- 

 mals, since they regarded the ei!;g strings as antenna^ and printed their 

 figures upside down. 



But the figures were accurate (Miough to show that these Avere really 

 parasitic copepods belonging to the family under discussion. Miiller 

 in 1776 showed that these '* antenna'" wei'e eo;^^ strings, and he also 

 found and described the true antenna\ But he blundered in regard 

 to the eyes as badly as his predecessors had done in regaixl to the anten- 

 nie, mistaking for them the sucking disks on the frontal plates and fail- 

 ing entirely to find the true ca'Cs. Hence he introduced his specimens 

 under the genus name Blnoenlux^ a name which survived for many 

 years. Slab})er (1778) descrilx^d and pictured one of the Caligina? 

 under the name Onixcux lutonux; he also delineated the antenna^^ and 

 many of the other appendages correctly and his figure is right side up. 

 Miiller in a second paper (1785) corrected his previous error 1)}- dis- 

 covering that the sucking disks were not eves. He then realised that 

 these copepods could no longer be classed in the heterogeneous group 

 known as Binocidus^ and accordingly founded for them the geiuis 

 CaliguK. 



But again he blundered, for the very name" tells us that he did not 

 find the true eyes, but considered these parasites to be blind. 



Stroem (1762) was the first to stud}" the habits of the genera from 

 living s})eciniens, and he has given us many interesting observations. 

 A few additional data have been given by Leach (1810-14), Lamarck 

 (1818), Johnston (1821:), Desmarest (1825), Burmeister (18:38), Rathke 

 (1843), Baird (1850), Kroyer (1863), Heller (1865), Claus (1875), 

 Hesse (1877, 1883), and T. Scott (18;)4, 1900). 



But although this list of names looks (juite formidable they have 

 really given us almost nothing upon the habits and development of 

 the group. Johnston established for the first time the external difi'er- 

 ences in the sexes of CaHgns ])\ describing in detail a male and a 

 female of C(il!.gn>i eurtnx from the cod. 



« Caligus, from caligo, a medical term for blindness or weakness of the eyes. 



