SLAVINA AISTD OPHIDOlSrAIS. 267 



The latter differs from other species of Slavina in the arrange- 

 ment of the dorsal bristles and in its greater size. 



The dorsal bristles are often wanting altogether in many ol 

 the segments ; about the middle of the worm thay are generally 

 arranged, for the space of a few segments, with some approach to 

 regularity ; but in the anterior and posterior portions only an 

 isolated segment here and there bears one, frequently unpaired. 

 There is only one bristle in each bundle when present, a short 

 straight bristle, slightly toothed at its outer extremity, which 

 does little more than just appear through the integument, with a 

 shoulder at about the junction of the outer fourth with the rest 

 of the shaft. 



The touch-organs are irregularly disposed, but usually more 

 or less in rings, very numerous on the head, as shown in the 

 drawing (fig. 5), less so on the body, whilst toward the posterior 

 part they are often arranged almost in the same manner as in 

 Slavina lurida. The eyes are blackish-brown, and the corpuscles 

 of the perivisceral fluid spherical and granular. There are usually 

 four streaks of greenish-brown pigmentary matter on the first 

 five segments. 



The above characters on the whole, I venture to think, justify 

 the incorporation of this annelid with the genus Slavina ; the 

 reasons for this course rather than the converse one of trans- 

 ferring the species of Slavina to the genus Ophidonais, being that 

 the arrangement suggested by Grervais has met with but small 

 favour ; and that as his genus Ophidonais includes but the one 

 species, it seems preferable to do away with that rather than 

 with the one proposed by Vejdovsky in the work which, after all, 

 must at present be regarded as the standard of reference, con- 

 taining, as it does, the only attempt which has hitherto been 

 made to give a complete account of the Oligochseta as a whole. 



I propose, therefore (retaining the specific names), to call the 

 worm which I have last described Slavina serpentina, and the 

 former one Slavina lurida, the following being a short resume of 

 the genus. 



Family Naidomorpha, Vejdovsky. 

 Grenus Slayina, Vejdovshy. 

 Annelids provided with papilliform elevations of the cutis 

 (touch-organs) usually arranged in rings ; inhabiting cases formed 

 of debris agglutinated by a mucous secretion from the bodies of 

 the bearers. 



