NEW ANNELIDS. 



275 



The main points of difference from Benham's type are to be 

 found in the much diminished size, the position of the gizzards 

 and hearts, and the segment which marks the commencement of 

 the intestine. If we place these points side by side their value 

 will at once be seen. In column I. I give details of the sub- 

 species of T. lankesteri, in column II. those of the type, and in 

 column III. the particulars relating to the new species : — 



Details. 



I. 



11. 



III. 



Length 



240-280 mm. 



580 



4-6 mm. 



5,6,7 



Last in 13 



? 



? 



? 



? 



7,8,9 



? 



13 



15 mm. 



Segments 



Diameter 



50 

 1 mm. 



Gizzards 



9, 10, 11 



Hearts 



Principal in 12, 

 13, 14 

 19 



Intestine begins 



If we turn to the allied genus Benhamia, we find that the 

 species range from 16 mm. in length in B. curta to 540 mm. in 

 B. rosea, so that we are prepared to find a similar divergence in 

 Trigaster. I should assume that the new species may grow to 

 double the present dimensions when adult, but the very limited 

 number of segments shows that it is comparatively a pigmy 

 form. Unfortunately, the very juvenile condition of the specimen 

 renders it impossible to say anything about the sexual organs, 

 but in every other respect our information is definite and con- 

 clusive. 



On account of the small size and the paucity of segments I 

 propose for this new annelid the name Trigaster minima. 



