A KEY TO BRITISH HEN LEAS. 87 



sent they usually occur at the point where the oesophagus merges 

 into the intestine. They may also vary in number; and few 

 characters are more helpful to the systematist than these glands. 

 They are not found in H. tenella, H. marina, H. curiosa, H. 

 lampas, and some others, and we name this group Henleanella. 



Salivary Glands are present in H. curiosa, H. rosai, H. 

 dicksoni, and H. tenella, among others. They vary a good deal 

 in size, shape, and position. In H. inusitata and H. alba we 

 find glands of a special nature. 



Spermathecje are present in all adults. In H. puteana there 

 are two pairs. This, however, is unique, not only in the genus, 

 but in the family. In all the other species one pair is found 

 opening in the intersegment 4-5. There are no diverticula, as 

 in Fridericia, but glands are frequently found near the external 

 aperture, as in H. marina and H.fridericioides. H. attenuata has 

 never yet been found adult, though the species is far from rare. 



The Dorsal Vessel usually takes its origin in front of the 

 girdle, and may frequently be seen as a white sac or a kind of 

 pump, throbbing and pulsing vigorously. It is not unusually 

 found near the oesophageal glands, about segments 7-9 ; but 

 some of the more recently discovered species show the presence 

 of the vessel in or behind the girdle, as in Enchytrceus and 

 Marionina. These may eventually form a new genus. In 

 Fridericia its position is usually between segments 15-20, or 

 even further back. The blood is always colourless. 



Septal Glands are present in all known species. The 

 normal number is three pairs, situated in segments 4-6 ; but 

 the number occasionally varies. In one species, which I formerly 

 described as H. tenella, but now regard as a new species, we find 

 four pairs of septal glands. The same applies to the new species 

 described above as H. trisetosa. This number is exceeded in 

 some other Enchytrseids, but is not at present known to occur 

 in any other species of the genus Henlea. One species in each 

 group has only two pairs. 



Ccelomic Corpuscles occur in all Enchytraeids, and vary 

 greatly. Some species of Henlea have corpuscles which look 

 like horny discs. They are round or oval and brown, almost like 

 encysted protozoa. Others conform to the regular type. 



Though each species has its distinctive characteristics, some 



