ON A NEW HISTRIOBDELLID. 30:^ 



about ten miaute lobes. A large mass of unicellular glands 

 {I. gld.) lies just within the base o£ each leg, and the numerous 

 ducts open on the terminal lobes. The expanded terminal 

 part (foot) of these appendages is strongly adhesive — not 

 owing to any sucker-like action, as there is no muscular 

 arrangement for bringing this about, but on account of the 

 sticky character of the secretion of the gland. On the 

 posterior border of each leg is a short cylindrical tentacle or 

 cirrus (c*^), tipped with motionless cilia; and close to its base 

 lies a shorter process of similar character. 



Stratiodrilus differs from Histriobdella homari, as 

 regards the external features, mainly in the presence of the 

 cirri, of which there is no rudiment in the latter form. The 

 anterior and posterior limbs and the claspers, though differing 

 in minor points, are very similar in essentials. Foettinger 

 has, however, failed to distinguish the adhesive glands of the 

 posterior legs, with their ducts, from the muscular fibres that 

 run close to them. He says, "Nous avons ici, comme dans 

 les pattes anterieures, un amas de cellules musculaires 

 coiuposees de deux parties, une centrale, cellulaire avec 

 noyau et une peripherique, sous forme de fibre. Tons les 

 fibres se dirigent vers I'extremite elargie du menibre, et se 

 terminent en divergeant a pen de distance de son bord 

 aminci."^ But the fibres referred to are the ducts of the 

 glands, and the secretion may frequently be seen oozing 

 through their fine terminal apertures. The greater develop- 

 ment of the cephalic tentacles in Stratiodrilus is a minor 

 point of difference. 



P. J. van Beneden's description of the extraordinary move- 

 ments of Histriobdella applies so well to the form at 

 present under consideration, that they may be quoted. "On 

 pent dire sans exageration que c'est un ver bipede ou meme 

 quadrupede, quand il se deplace sur une plaque de verre, ou 

 tout autre corps uni. Que Ton se figure un clown de cirque 

 le plus completement disloque possible, nous alliens meme 

 dire entierement desosse, faisant des tours de force et 



1 Jj. c, p. 459. 



