no. 2267. 



NEW BRANCHIOBDELLID WORMS— ELLIS. 



245 



entire ; margins of the lips bearing a few short, transparent bristles ; 

 tooth formula usually 5-4 or 5-5, varying from 4-3 to 6-5 ; upper jaw 

 usually type V, lower jaw type V or type VI; tooth plan of both 

 jaws c-B-A-B-c, upper jaw sometimes c-B-A-B-c-d; width of lower 

 jaw 24 micra (in worm 1.4 mm. body length) to 30 micra (in worm 

 2.8 mm. body length) ; major pharyngeal diverticula three, two dorsal 

 and one ventral, the ventral diverticulum about midway between 

 the levels of the two dorsal diverticula ; anterior nephridia alternat- 

 ing in segments II and III (of 44 specimens ex- 

 amined on this point 25 had the nephridium in 

 segment II on the right side and that in segment 

 III on the left; 17 had the nephridium in segment 

 II on the left side and that in segment III on the 

 right; and two individuals had both nephridia in 

 segment II) ; anterior nephridia opening to the 

 outside through separate pores on the dorso- 

 lateral surface of segment III; spermatheca in 

 segment V, composed of three parts, a short muscular portion near 

 the spermathecal pore, a middle tubular portion and a dorso- 

 posterior, globose portion ; testes in segments V and VI ; vasa defer- 

 entia from segments V and VI joining the atrium in segment A'^I; 

 no accessory sperm tube; alimentary canal straight, passing through 

 the body near or along the mesial axis, somewhat expanded in seg- 

 ments I and II, strongly sacculated in segments III and IV, much 

 narrowed in segments V and VI, slightly expanded in segment VII, 

 npri'owing from segment VII to the anal opening on the dorsal 



surface of the anterior half of segment X (in 



surface view the anus appears to open in the 



posterior half of 



tions shoAv that 



segments IX and 



of the alimentary; 



PIG. 3.— Upper jaw op 



T YPE-SPECIMEN OF 



\'[l):^)D1IL us FORMO- 



SUS ELLIS, FROM AN- 



l> 3 I i ) V . INDIANA . 



TYPE V . 



segment IX, but sagittal see- 

 the anal opening is between 

 X and that the rectal portion 

 canal is carried by segment 

 X); caudal sucker ventral; smallest specimen ex- 

 amined 0.8 mm. in length; largest 3.1 mm. (pre- 

 served specimens). 

 A summary of the variations found in the number of teeth in this 

 species is given below : 



Table 1. 



Fig. 4.— Lower jaw 

 of type-specimen of 

 xironodrilus for- 

 m0su3 ellis, from 

 anderson, indiana. 



TYPE VI. 



