682 PATAGONIAN EXPEDITIONS! ZOOLOGY. 



and of nearly the form shown by G. scutifera. The posterior sucker is 

 relatively larger than in G. michcelseni and, unlike that species, faces 

 ventrad and extends further forwards. At the same time its posterior 

 margin is widely exposed from above. Its surface is roughened with 

 numerous minute papillae (Plate L, fig. 24). A somewhat irregular series 

 of small cutaneous papillae passes along the median dorsal line, usually 

 occurring on every annulus from the genital somite nearly to the anus. 

 Anterior to the genital pores they usually fade out and may be absent 

 from several of the preanal somites also. These papillae form a strictly 

 median series, not a broken double series as in G. lineata. They have a 

 nearly constant relative size on the three annuli of a somite, being longest 

 on a2 and smallest, and sometimes even wanting on ai. 



MEASUREMENTS OF TYPE. 

 Total length, 9 mm. 



Length to male pore, 2.5 mm. 



Diameter of anterior sucker, 6 mm. 

 Diameter of posterior sucker, 1.2 mm. 

 Width of body at male pore, 2 mm. 

 Depth at male pore, .6 mm. 



Greatest width (XVIII), 3.7 mm. 

 Depth at XVIII about, .8 mm. 



Annulation. I and II are coalesced. Ill and IV are uniannulate, the 

 latter containing the eyes. V is biannulate, the first annulus about as 

 long as the entire somite IV, the second (0,3} about three fifths as long. 

 The furrow V aila2 is sometimes faintly developed. VI is triannulate, 

 a2 generally, but not invariably, the longest. 



The annuli of the complete somites, of which there are nineteen (VI to 

 XXIV), have, with the exception of the first and the last, which may vary, 

 a constant relative size ; a2 is the longest, ai the shortest ; ai has four 

 circular muscle-bands on the dorsal side, a2 and 0,3 have each five, except 

 that in most cases XXIV aj has but four. XXV is biannulate both dor- 

 sally and ventrally. XXVI and XXVII are uniannulate, the latter deeply 

 cut by the large anus. One distinct postanal annulus is differentiated 

 (Plate L, figs. 23 and 24). 



Unlike most of the material in this collection, which was not suitably 



