NEW MORPHOLOGICAL AND PHYSIOLOGICAL DATA 229 



New Data 



Apart from indicating that the nema phylum can be divided into valid, nat- 

 ural orders on the basis of the structure of the mouth parts and related organs, 

 this article records numerous additions to our knowledge of the morphology of 

 nemas. Facts announced in a sentence or two, or through the medium of illus- 

 trations, might perhaps have been advantageously made the subject of separate 

 papers. Among these additions to our knowledge, the following may be 

 mentioned: 



1. In a miscellaneous lot of over one hundred new genera of nemas, thirty per 

 cent prove to have jointed setae. Probably a much larger percentage have 

 jointed setae. Among the nemas having setae, jointed setae are probably 

 the rule rather than the exception. 



2. The distal ends of the cephalic setae sometimes exhibit considerable com- 

 plexity, indicating that they are specially developed sense prgans; e.g., in 

 Linhomoella and Crystallonema. 



3. Additional evidence that bilateral mouth-parts arise by elimination of dorsal 

 elements exists in Pseudonchus. 



4. There is a large group of nemas with six well-developed onchia having an 

 outward stroke, adapted for digging; e.g., Apodontium and relatives. 



5. More than ever, it is clear that amphids are practically universal among the 

 free-living nemas. They may be small and difficult to see; as in Stilbonema 

 and Laxonema. In the p_ast, they have been sometimes overlooked. Some 

 Triplonchs possess amphids; e.g., Onchium, Triplonchium. 



6. All amphids have backward connections, often, perhaps always, tubular and 

 containing coagulable substance. Of unusual interest are the huge glands of 

 lonema. 



7. Lateral series of organs occur in so many of the genera described, as to lend 

 additional weight to the opinion that such series are a normal element of the 

 nema structure. 



8. There is much additional evidence of differentiation of form and structure 

 among the various cells of the intestine. 



9. The presence of oesophageal glands is established for Axonchium and its rela- 

 tives, (Dorylaimus, etc.) They occur in the posterior enlargement of the 

 oesophagus, one emptying into the lumen dorsally in its anterior part, and 

 often two others emptying into the lumen farther back. 



10. Non-terminal spinnerets and mouth openings seem practically always ven- 

 tral; e.g., Trissonchulus, Campylaimus. 



11. A large unicellular gland is connected with each supplement of the males of 

 Bolbella and Eurystoma. 



12. The presence of pairs of cloacal glands in the male, first observed by de Man 

 in Euchromadora, is established for many other genera. 



13. Cytolaimian transition-forms exist between the parasitic and free-living 

 nemas; e.g., Monhystrium. 



14. The existence of double-jointed spicula is established for Rhips and Xinema. 



15. Nemas are disclosed in which the sperm cells are of extraordinary size; such 

 species may prove useful in studies in genetics. 



16. Rhynchonemas are distributed in various oceans. They are free-living nemas 

 with beak-like heads, but otherwise normal in form. Presumably, this beak 

 serves to extract food from receptacles the entrances to which are narrow. 



17. There is a marked absence of syngonism in marine forms. 



18. The existence is demonstrated of special spermatheca, in the form of special 

 separate branches of the female sexual organs. 



