182 ANCEID^. 



some accident, have lost the mandibles, which are now 

 undergoing reproduction. 



The oral appendages of the female also undergo a great 

 change. As in the male, the lanceolate organs of the 

 mouth are lost ; but, unlike the male, they are replaced 

 by no other appendages. Dissection shows us that they 

 have neither mandibles nor the anterior pair of maxillae. 

 The only appendages which the female adult Anceus has 

 upon the oral surface of the cephalon, are the maxillipods 

 and a pair of gnathopoda, and even these are so depreciated 

 in character as to become rudimentary rather than nor- 

 mal appendages. The maxillae consist of four gradually 

 diminishing joints, supported on a broad base that has 

 the antero-median angle produced to a blunt point. The 

 gnathopods are reduced to two or three joints, at the 

 base of which, on the internal surface, is a broad, exqui- 

 sitely thin, membranous scale.* 



Still more remarkable, beneath these appendages there 

 appears to be neither mouth, stomach, nor alimentary 

 canal. 



The immediate assumption of every carcinologist will 

 be that we may have mistaken exuvia, or cast skin, for the 

 animal. With the exuviae all the appendages, together 

 with the stomach and alimentary canal, are thrown off. 



* Tliis delicate membrane is unnoticed by Hesse and other previous 

 writers. It occurs only in the adult females, and is perfectly identical in its 

 character with the membrane forming the outer cover of the ovigerous sac. 

 If we suppose the large outer pair of appendages of the mouth of the female 

 to represent the second pair of legs or gnathopoda, we at once arrive at the 

 conclusion that this membrane is portion of the ovarian sac, which normally 

 exists in this position (see figure of Paranthura), and, indeed, in the females 

 of the Irish species it seemed to us, on dissection of several specimens, to be 

 actually continuous with the membrane within the first pair of true legs, and 

 to form, in fact, a jugular opening of the pouch, whence we extracted several 

 of the young, the antennae of one of which was actually inserted between this 

 pair of supposed gnathopods of the female. See the upper right hand figure 

 in page 190. 



