452 THE AMERICAN NATURALIST [Vol. LIV 



plane with the anus, I can not accept MacCallum's conclusion. 

 He says "that the vagina has not been seen, but appears to be 

 very near the mouth on the left side." If it were not near the 

 middle of the body and in the mid ventral line I would accept 

 with some caution his conclusion, because this is the character- 

 istic position of the vulvar opening in this genus. 



MacCallum's C. cyathocephalus is clearly the fourth stage of 

 his C. scabrm. I have described in detail this same stage for C. 

 americanus. 



Unfortunately the description of C. bungari is so incomplete 

 and the drawing so obscure that it is impossible to locate the 

 worm even with regard to its genus. Certainly with the slight 

 description given it could not be placed in the genus Camallanus, 

 because of the single portion of the esophagus and the type of 

 the oral apparatus. The picture seems to show eggs in the ter- 

 minal portion of the uterus; if the worm were mature, larva* 

 only would be found in this portion of the uterus if it belonged 

 to the genus Camallanus. 



Since I have found C. americanus in many different species 

 of turtles in the United States, I have tried to decide whether or 

 not MacCallum found this species and described it as one of his 1 

 new species. In going over his paper carefully I am unable to 

 admit that from his descriptions and figures he described the 

 worm I recorded under the name Camallanus americanus, al- 

 though it is possible that he might have had the worm. One can 

 not be certain whether or not he had some of the species described 

 by Leidy, nor can one be certain of the validity of any species 

 which he describes. 



In the face of these facts it seems to me that at present it 

 would be impossible to accept these species in the genus Camal- 

 lanus and hence I suggest that they be considered as species in- 

 quirendm. Camallanus is such an important genus that the 

 species described within it should be established without any 

 doubt whatsoever. It is unfortunate that MacCallum did not 

 publish more definite data concerning the forms and it is to be 

 hoped that he will follow up his paper with a complete descrip- 

 tion of each worm, based on the study of more material and his- 

 tologic sections. 



In the past, nematode descriptions have for the most part been 

 rather superficial and a great deal of confusion has arisen con- 

 cerning the identification of genera and species. The worms are 



