British Enchytrseids. By Rev. H. Friend. 133 



by me at several places in Derbyshire between February 1911 and 

 July 1912; at Hastings, June 1912; and Sedlescombe, Sussex, 

 August 16, 1913. 



/3. The Genus Acileta. 



This interesting genus is characterized bv the absence of setae. 

 In some instances setae sacs still remain in the form of ccelomic 

 processes slightly attached to the body-wall, while in others these 

 vestiges have entirely disappeared. Michaelsen (4-) has three 

 species only, known to science in 1900, all of which are British. 

 Bretscher (8) in 1902 added a fourth, which has not yet been 

 found in these Islands. Southern (-5) has described an Irish 

 species, and to these I am now able to add two others. 



1. Achasta spermatophora Friend. 



Length about 8 mm. Segments from 35-40. Setre sacs pre- 

 sent dorsally. Brain large, nearly oval, convex before and behind, 

 about 1^—2 X 1. Characterized by a pair of bodies resembling 

 spermatophores, whence the specific name. First described in 

 Irish Naturalist for September 1912, p. 174. 



2. Achseta incisa Friend. 



Length at rest about 5 mm., extending to 7 or 8 mm. when 

 stretching eagerly, when it is very slender. Segments 35-40. 

 Destitute of setse, but possessing dorsal setse sacs. Owing to the 

 presence of large opaque coelomic corpuscles and chloragogen cells, 

 it resembles Enchytr&us nigrinus under the Microscope. Sperm- 

 funnels 2 or 2^ times as long as broad, with long sperm duct, 

 medium atrium and pores. Three pairs of septal glands, but no 

 salivary glands observed. Dorsal vessel arises in segment 7 and 

 pulsates in front, especially in segment 6. Nephridia in 6/7, 7/8 

 with very large postseptal. Behind the girdle the nephridia show 

 the postseptal narrowing into a duct. Spermathecae bottle-shaped, 

 with neck opening into the oesophagus ; not like those of A. bohemica. 

 Brain about 2-3 times as long as broad, sometimes incised behind, 

 suggesting the specific name. The brain (fig. 17) was found, after 

 this specific name had been given, to be variable, but the name is 

 retained as the other characters are sufficiently definite to ensure 

 recognition. 



Habitat. — Sandy soil, Mansfield, Notts, May 8, 1912. See 

 Trans. Notts Nat. Soc, 1911-12, pp. 58-9. No figures were 



