76 PROCEEDINGS OF THE NATIONAL MUSEUM. vol.46. 



that in case their descriptions are confirmed the generic diagnosis 

 above given will need revision. 



It seems that Jagerskiold might have even gone further and said 

 that if R. cristata were found to have only one row of ventral spines 

 extending, as Frolich describes and figures it, from the head to the 

 vulva, then it would be necessary to leave it as the type and only 

 species of its genus and create a new genus for the several other 

 species at present assigned to this genus and which have two rows 

 of ventral spines or combs extending from the head practically the 

 entire length of the body. There is, however, some little evidence for 

 believing that Frolich and Dujardin were both in error in stating that 

 R. cristata has only a single row of spines. 



In the first place, it is a very easy matter to get the impression that 

 a species of Rictularia has only a single row of spmes. It was my 

 own unpression of R. splendida when I first looked at it. No other 

 species of Rictularia was known to either Frolich or Dujardin, so 

 they had no contradictory statements or material for comparison to 

 make them particularly careful in regard to this point. Moreover, 

 they worked at a time when nematodes were none too carefully 

 described, and their descriptions of this species are iii error in some 

 other respects. More important yet is the fact that both of them 

 have evidence in their papers that their statements in regard to the 

 number and extent of the rows of spines is not correct. Tlius Frolich 

 states that there is but one row of spines, but his figure 3 of plate 1 

 shows the row of spines to be distinctly latero-ventral in its relation 

 to the buccal capsule, and his statement in the label that the spines 

 are turned sideways leaves it still likely that a corresponding row on 

 the opposite side of the body was not seen. Dujardin offers confir- 

 mation of this idea when he states that the cuticle bears from the 

 head to the vulva an asymmetrical rank of hooks. The suggestion 

 of asymmetry probably arose from seeing both rows of hooks in the 

 head region, where they were close together and yet evidently not in 

 the same focal plane. Probably influenced by Frolich's statement 

 and by his own first observation, he held to the idea that there was 

 only one row, qualifying it to conform to other observations by the 

 statement that the row was asymmetrical. Frolich apparently only 

 saw one row and did not mention or figure any asymmetry. Dujardin 

 also states that the vulva is located laterally toward the dorsal face 

 (taking the position of the buccal aperture, which is dorsal, as deter- 

 mining the ventral surface) , and it seems evident that he considered 

 the ventral (to him dorsal) line as determined by the row of spines 

 and the vulva at its side as located laterally or asymmetrically. 

 The actual fact must have been that the vulva was in its usual 

 approximate ventral location (it is a little lateral in R. caMrensis and 



