440 r. W. GAMBLE. 



tiou or the other, right through the group. SpengeFs^ Latinised 

 form of " Alloiocoela " (Alloeocoela) is adopted. 



II. Systematic. 



TURBELLARIA. 



Sub-order 1— RHABDOCCELIDA. 



A. ACCELA. 



A digestive cavity absent. Mouth ventral, leading 

 indirectly through the pharynx into the paren- 

 chyma. A "frontal gland'^ and otolith present. 

 Nervous system consisting of a brain and peri- 

 pheral nervous sheath. Hermaphrodite. Testes 

 follicular, rarely compact. 



Family PROPORIDiE. 



Acoela with a common genital pore. 



Genus 1. — Proporus, v. Graff 

 (= ScHizoPRORA, Schmidt, 28). 



Proporidae without spermotheca.^ 

 1. Proporus venenosus (O. Schmidt, 28). 



Length 1 mm. Body elongate, cylindrical, rounded at 

 both ends. Colour bright yellow, due to diffused granular 

 pigment. Epidermis ciliated, containing numerous rhab- 

 dites, some free, some grouped in formative cells. These 

 pyriform groups are specially abundant towards the hinder 

 end, giving a spinous appearance to the surface. The mouth 

 lies just beneath the anterior end ; circular at rest, it becomes 

 slit-like during movement. The pharynx is a direct invagi- 

 nation of the anterior end (v. Graff, ' Acoela,' pi. x, fig. 5). 

 It is long (one-fourth the length of the body), cylindrical, and 



' ' Getting, gelehrte Anzeigen,' March 1st, 1884, p. 183, note. 



* The definitions of families, sub-families, and genera are taken from v. 

 Graff (53). 



