NO. 1573. PARASITIC COPEPODS— WILSON. 391 



The anal laminae next demand attention. They are modified so 

 peculiarly as to have deceived many of the investigators who have 

 examined only adult specimens. Leach, who founded the genus in 

 1816 upon two species, Pandarus hicolor and P. hoscii (really two 

 variations of the same species), described them as the notched apex 

 of the "abdomen." But this term ''abdomen" as he used it included 

 the genital segment and the sixth segment, as well as the true abdo- 

 men, which latter he seems to have entirely overlooked, since no 

 mention is matle of it. 



Many of the long list of observers since his day have likewise over- 

 looked the anal lamintr altogether or have designated them as a part 

 of the genital segment. Desmarest (1825), in his brief diagnosis of 

 this genus, twice mentions the "deux soies" at the posterior end of 

 the body. But since under the species diagnoses he states that these 

 "soies" are from one and a half to two times as long as the body, he 

 is evidently speaking of the egg strings, and no mention is made of 

 the anal laminae. 



Milne Edwards (1840) says: 



L'abdomen est court, et presente une structure tres singuliero- il se compose de 

 deux scgmens, dont le premier porte de chaque cote uu appendice, et se trouve recou- 

 vert au dessus par le second cpii nait pres de son bord anterieur, et a la forme d'une 

 lame caudale (p. 466). 



He is thus the first to definitely recognize any appendages in this 

 part of the body, but he evidently found considerable difficidty in 

 the arrangement of the "two segments" of the abdomen, since what 

 he calls the "second" arises from the anterior border of the "first" 

 and lies directly over the latter. This would be a mistake, however 

 we may regard the "appendages," since it would assign them to the 

 "first" or basal segment, when they are plainly borne on the terminal 

 segment in the young female (Plate XXXII, fig. 182). 



Dana (1852) seems to be the first to recognize these appendages as 

 actually anal laminae. In his diagnosis of this genus he saj^s : 



Abdomen two to three jointed, second segment posteriorly rounded, and having 

 on the sides the caudal stylets, last segment concealed below the second. * * * 

 Caudal stylets styliform, acute, nearly naked (p. 1364). 



In all his descriptions Dana regards the genital segment as the 

 first segment of the abdomen, hence his "second segment" would be 

 this dorsal plate or lobe, while his "last segment" would be the true 

 abdomen. 



He thus reverses the arrangement given by Milne Edwards and 

 presents the segments in their true sequence, but the "caudal sty- 

 lets" are not attached to the sides of the dorsal lobe, nor are they 

 connected with it in any way; they arise from the sides of the true 

 abdomen, his "last segment." 



Heller (1865) gives as the conclusion of his genus diagnosis: 



Annuhls genitalis su1>quadratus, jjostice angustior, angulis jjosterioribus acutis 

 Cauda ovalis, stylis duplo longioribus. 



