256 PROCEEDINGS OF THE NATIONAL MUSEUM. vol.55. 



C. philadelphica (Leidy) and C. chirocephala, new species, have 

 several characters in common with members of the genus Steqyhano- 

 drilus as defined by Pierantoni in his Monografia dei Discodrilidae, 

 1912.^ One of these characters, " the plurilobate prostomium " is 

 particularly noteworthy in this connection as it is used by Pierantoni 

 to differentiate StepTmnodrilus in his generic key. The two species 

 C. philadelphica and G. chirocephala have lobate lips similar to the 

 lips of StephaTwdrilus japonicus Pierantoni as figured by Pieran- 

 toni.^ Neither Stephanodrilus koreanus Pierantoni nor Stephano- 

 drilus japonicus Pierantoni, however, are figured with accessory 

 sperm tubes, and the accessory sperm tube is present in species of 

 C amharincola. Pierantoni also figures Branchiohdella digitata 

 Pierantoni, a species having but a single pair of testes, (Pierantoni), 

 with a plurilobate prostomium, showing that the lobate lip character 

 occurs in that group of species. No data concerning the pharyngeal 

 diverticula of Pierantoni's species were obtainable. 



a\ Upper and lower lips entire excepting a small, median emargination ; not 

 divided into lobes which may be extended as tentacles; two small lobes 

 present in the median emargination of the upper lip in species with dental 

 formula 3-4. 



&\ Dental formula 5-4. 



&, Middle tooth of the upper jaw long and prominent, the lateral 

 teeth of the " c " and " b " orders, small. G. macrodonta Ellis, 

 c*. Middle tooth of the upper jaw longer than the other four teeth, 

 but small enough so that all five teeth may be considered as 

 almost subequal ; lateral teeth of the " c " and " ft " orders 

 from one-half to three-fourths as long as the middle "A" 

 tooth. C. vitrea, new species. 

 h". Dental formula 3-4 ; middle tooth of the upper jaw long and promi- 

 nent, lateral teeth small ; teeth of the " c " order wanting. C. 

 inversa, new species. 

 «*. Upper lip composed of four subequal lobes, which may be extended as digiti- 

 form tentacles; lower lip composed of two subequal lobes which may be 

 extended also; a small lateral lobe on each side at the junction of the 

 upper and lower lips. 



d\ Dental formula 5-4, middle tooth of the upper jaw long and 

 prominent ; lateral teeth of the " c " and " & " orders small, 

 one-half the length of the middle tooth or less ; jaws subequal, 

 the upper slightly larger than the lower. C. philadelphica 

 (Leidy). 

 d*. Dental formula apparently 1-4, but actually 5-4; middle tooth 

 of the upper jaw long and prominent, lateral teeth of the " c " 

 and " 6 " orders very small, not exceeding one-sixth the length 

 of the middle "A" tooth; upper jaw much larger than the 

 lower, from one and three-quarters to three times as wide as 

 the lower jaw. C. chirocephala, new species. 



1 Annuarlo del Museo Zool. della B. Univ. NapoU, n. s., vol. 3, num. 24, Feb. 29, 1912, 

 pp. 1-28, pi. 5. 



