GASTROTRICHA 

 15 (14) Dorsal spines simple; i.e., without lateral barbs 



627 



or pointb. 



16 (17) Anterior region sharply set off from narrow "neck" region. 



Chaetonotiis Jormosus Stokes 1887. 



Length 0.169 mm. Oral ring minutely beaded. Head thn-e l<,l,cd. I)„rsal and lateral 

 aspects of body covered with short tine recurved spines with slight basal cnlarRcmcnls -but 

 without scales.^. Spines all subequal, in length 0.0292 mm., or less. Trenton. New Jcr«v 



No figure pubhshed. j ■ ^> • 



17 (16) Transition from anterior region to body gradual, not sharply market! 

 at any point ' ,^ 



18(19) Head rounded Chaetonolus brcvispi)wsus ZcV\n\i-d iHH(}. 



Length of body 0.095 to 0.149 mm., of esophagus 0.0223 mm- 

 Spines somewhat curved, remarkably short, slightly larger poste- 

 riorly, arranged in eleven rows Head circular in front, with four 

 eye-spots. The only American species reported ni(jrc than ontc. 

 Orono, Me., and Trenton, New Jersey. It is the C. larus of Stoke-, 

 also of Fernald. 



Fig. 971. 



Chaetonolus brevispinosus in dorsal view, X a^K), with spioiMC 

 scale more highly magnified, (.\fter Zelinka.) 



19(18) Head five lobed Chaetonof us ncdnt/iodes Siokcs i^S-;. 



Length 0.1411 mm. Body covered with scali-s which In-ar eaih a 

 small supplementary scale; the latter in the anterior region iios-st-s-^t-i 

 a short, curved spine; just behind the middle of the IhkIv these trrnu- 

 nate in a cross row of larger spines. t)n each side near the laudal 

 processes are two larger curved spines. Trenton, New Jer>cy. 



Fig. 972. Posterior end of Charlonotus acanlht>dfs in dor^;d virw. 

 X about 570. (After Stokes.) 



