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cobb: further notes on tricoma 481 



to obscure the natural relationships of the species. These first 

 came to light thru a careful microscopic investigation of the 

 internal anatomy. 



Tho the published figures mentioned above are accurate so 

 far as they go, they are unfortunately incomplete, and this in- 

 completeness of observation led to the adoption of a generic 

 name, Tricoma, which is misleading. Instead of three cephalic 

 setae, there are four. Later researches have shown that the 

 setae on these worms are very fragile, and even now, in spite 

 of the examination of a larger number of specimens, a full knowl- 

 edge of the setae has not been obtained. It is certain, however, 

 that all the known species possess four cephalic setae. 



During visits to the Island of Jamaica I have latterly come 

 across a second species of Tricoma, inhabiting marine algae and 

 adjacent sand. As very few specimens were found, the infer- 

 ence is that the individuals are not common. All those found 

 came from near low tide mark on open, rocky sea-shores subject 

 to the unosbstructed action of ocean waves. Soon after dis- 

 covering the Jamaican species I received, thru the kindness 

 of my friend, Mr. F. Muir of Honolulu, a collection of free-living 

 nematodes from Larat, an island off the east end of New Guinea, 

 and in this collection also there were a few specimens of Tricoma. 



Prof. E. Bresslau, writing from Strassburg, informs me that 

 he observed a specimen of Tricoma cincta on the coast of Heligo- 

 land in the North Sea. 



It thus appears that Tricoma is a genus having a very wide 

 distribution. 



The accompanying figures are largely self explanatory. It 

 is only necessary to add a few words concerning the missing 

 features. 



The single cephalic seta, c, was drawn from another specimen 

 on which it grew. The setae, bb, drawn with dotted lines, are 

 reconstructions on the basis of the seta, c. Here and there on 

 the figures irregular scattered setae are shown. These are the 

 ones that actually existed on the specimen drawn. The dots 

 indicate the annules of the cuticle on which the stumps of bro- 

 ken off setae were observed. It will be seen, therefore, that 



