no. noi. PARASITIC COPEPODS—CALIGIDM— WILSON. 493 



"Schwanzanhange," in his Latin diagnoses as "appendices caudales;" 

 Claus calls them "Furcalanhange," in Latin "foliola candalia;" 

 Grerstaecker designates them as "Endgabel (Furca);" while Bassett- 

 Sniith speaks of them as ''caudal plates." 



There are several objections to these names. In the first place, most 

 of them preserve in some form the old name of "tail," given to the 

 abdomen, which was entirely a misnomer. 



The use of "furca" or "fork" is even worse, for we alread}^ have a 

 tuna upon the ventral surface of the carapace, and the repetition of 

 the name for a very different appendage could not but breed confu- 

 sion. Why not apply to them the term "anal," since they are always 

 situated beside the anus, and thus get a term to which there could be 

 no objection as a misnomer and which would be free from any danger 

 of confusion \ Let us call them, then, anal plates or lamina?, as we 

 called the appendages in the Argulida?, similar in position but differ- 

 ent in shape, anal papilla?. 



There is thus a cephalon bearing seven pairs of appendages, a thorax 

 of five segments, each bearing a single pair of appendages, the first 

 three united with the cephalon, and an abdomen of from one to four 

 segments, the last of which bears the paired anal lamina?. 



The cephalo-thorax is strongly flattened dorso-ventrally and is cov- 

 ered with a hard shell or carapace, which serves to protect the softer 

 parts underneath. In structure this shell is like that which covers the 

 anterior portion of the body in the Argulida?, but its shape is consid- 

 erably different. 



In the first place, the anterior antenna?, instead of being concealed 

 beneath the carapace, form a wide articulated border across its ante- 

 rior margin, their free ends standing out prominently on either side. 

 In six genera — < '<ii '!</ i/s, Pseudoad "tg //*, ( '< dig odes, Synestius, Homoiotes, 

 and r<i i''i i>, talus — the frontal plates thus formed carry upon their ante- 

 rior margins sucking disks or lunules. In the other genera they are 

 perfectly plain. 



These lunules often stand out prominently and, with the plates 

 themselves, give a squared appearance to the anterior margin (Plates 

 V, VI, XII). This is usually increased by an incision at the center 

 where the two plates meet, or by an emargination extending for some 

 distance on either side. In rare instances just the reverse takes place, 

 and the frontal margin is made pointed by a protrusion of the plates 

 between the lunules in the form of a beak or rostrum {Caligus Ka&rrm- 

 li'nis. irritant, and murrayanus). Either form presents a sharp con- 

 trast with the evenly rounded anterior margin in Argulus. 



Again, instead of a single median posterior sinus, there are two, one 

 on either side, leaving a median lobe between them, which is usually 

 half the entire width or more. 



Proc. N. M. vol. xxviii— 04 32 



