392 



PnOCEEDlNCrS OF THE NATIONAL MUSEUM. vol. xxxm. 



In the text he speaks of these appendages as "die seitlichen 

 Anliange" (p. 204) and "die seithchen Schwanzanhange " (p. 206), 

 but makes no attempt to explain them or their position. This, taken 

 in connection with the fact that he is so particular to designate them 

 as "seitlichen," would indicate that he did not recognize them as 

 anal laminae. 



Brady (1883), in his genus diagnosis, says clearly: 



Abdomen two or three jointed, rounded behind; caudal stylets borne on the side 

 of the abdomen, acute, styliform, nonsetiforous (p. 133). 



This, together with Dana's clear statement, ought to have estab- 

 lished the nature of these appendages, and yet we find Bassett- 

 Smith as late as 1899 giving a genus diagnosis in which he says: 

 "Genital segment terminating in two minute points, and at the base of 



the abdomen are two lateral, sharp, 

 dentate appendages" (p. 466). 



Nothing further is said in ref- 

 erence to them, and we are left to 

 interpret them as we please. 



That they are really anal lam- 

 inae is abundanth'' proven b}^ an 

 examination of the young of any 

 species. In some of these the 

 lamiufB are similar to those in 

 other genera belonging to this sub- 

 family, with the' single exception 

 that they are armed with nonplu- 

 mose spines instead of plumose 

 setae (see sinuatus, Plate XXXII, 

 fig. 182). 



As development proceeds the 



laminge change their position from 



Fig. 18.— The genital segment and abdomen the posterior margin to the base 



of the abdomen, at the same time 



OF Pandarus ceanchii, showing anal lam- 

 ina WITH TWO WINGS, DORSAL AND VENTRAL. 



becoming modified in form until 

 they finally reach the adult condition. In other species (bicolor, 

 cranchii, etc.) the laminae are changed considerably, even in very 

 young specimens, by a thickening of the outer margin and the addi- 

 tion of two wings, a dorsal and a ventral, on the inner margin 

 (fig. 18). _ 



As to the function of these specially modified anal laminae they 

 may perhaps serve as a guide to the egg-strings while the latter are 

 issuing from the genital segment. The openings of the oviducts are 

 widely separated and relatively close to the lateral margins of the 

 genital segment. Instead of passing directly back from their respec- 

 tive openings, and thus remaining some distance apart, the egg- 



