HIRUDO BOYNTONI, A NEW PHILIPPINE LEECH 



By Lawrence D. Wharton 



(From the Department of Zoology, College of Liberal Arts, University of 



the Philippines) 



Hirudo boyntoni sp. nov. 



Individuals of this species show a wide variation in size. The 

 following measurements are taken from a specimen slightly 

 larger than the average : Length in extension, 14 cm. ; length at 

 rest, 7 cm.; width, 12 mm.; thickness, 6 mm. The greatest 

 width is about the middle, and the body tapers toward both ex- 

 tremities, but more toward the anterior. The cephalic lobe is 

 broad and rounded in front. The acetabulum is circular, about 

 9 mm. in diameter, and attached in the center. 



On the dorsal surface the skin is divided into square papillae, 

 each annulus having from 16 to 20 of these papillae. When the 

 body is contracted the annuli are ridged. There are 102 dis- 

 tinct annuli, counting on the dorsal surface. The first 4 of these 

 form the cephalic lobe. The 5th and 6th annuli, called by Whit- 

 man the "buccal annuli," are fused laterally as are the post- 

 buccals, the 7th and 8th. In addition, the groove between the 

 6th and 7th disappears on the ventral surface so that all 4 of the 

 annuli form a broad lip ventral to the mouth. 



There are 5 pairs of ocelli borne on the 1st, 2d, 3d, 5th, and 

 8th annuli. In position the first pair corresponds to the median 

 pair of sensory papillae and the others to the inner lateral papil- 

 lae of the succeeding somites. These sensory papillae can first be 

 distinctly seen on the 5th annulus as small transparent spots. 

 There are 4 pairs on the dorsal surface — a median pair, an inner 

 lateral, an outer lateral, and a marginal pair — and 3 on the 

 ventral surface. After the 5th annulus they are found on the 

 8th, 11th, and 14th, and from there on to the 94th on every 5th 

 annulus. After this they are found on the 97th, 99th, and 101st 

 annuli. In addition, 8 radial rows of the organs can be seen 

 distinctly on the dorsal surface of the acetabulum. 



Using these sensory papillae as a means of determining the 

 somites, I find the body to be composed of 26 somites made up as 



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