130 MR. H. CHARLTON BASTIAN'S MONOGRAPH 
divided by a narrow constricted portion from the broad vas deferens.  Spicules and 
accessory piece united together; segments of former 455" long. Spermatozoa cylindrical, 
soyo” long, having slow oscillating movement. Ale two, composed of a hyaline mem. 
brane extending on each side from 545” above anus to posterior extremity, supported 
by nine rays in sets of one, two, and three. 
Hab. Marine, in sand from tide-pools, Falmouth. 
2, R. LONGICAUDATA, n. sp. (Plate X. figs. 63, 64.) 
Female, length +”, breadth 333". 
External Characters.—Body white, tapering gradually anteriorly, but more abruptly 
towards the posterior extremity, which is long and filiform. Head truncate, naked, 
Integument with longitudinal striæ, 19400 apart; transverse not recognized. 
Pharyngeal cavity cylindrical, 5566505 long by 5560 broad. (Esophagus 7th of total 
length. Intestine very broad at commencement, before it is compressed by genital 
organs; covered by only a very few scattered fat-particles. Anus 190 from posterior 
extremity. Vulva very slightly anterior to middle of body. 
Male, not seen. 
Hab. Sandy soil about roots of wheat, Broadmoor, Berks. 
3. R. oRNATA, n.sp. (Plate X. figs. 65-67.) 
Female, length 35", breadth 515". 
External Characters.—Body white, tapering anteriorly, but more posteriorly, where 
it is filiform. Head truncate, naked. Integument very transparent, with transverse 
strie 55000 apart; longitudinal not recognized. 
Pharyngeal cavity Ir long. (Esophagus about ith of total length. Intestine, just 
at commencement, devoid of hepatic granules; remaining portion sparingly covered with 
large and rather dark-coloured particles. Anus 545” from posterior extremity. Vulva 
exactly in centre of body. 
Male, length 3^, breadth 41". | 
Anus 359 from posterior extremity. Spicules not very broad, slightly curved, ae 
long, and connected with a posterior median accessory portion of one-half the length. 
Ale lateral, same as in R. marina. 
Hab. Between sheaths of leaves, stalks of wheat in stubble-fields, Broadmoor, Berks. 
4. R. acris, n.sp. (Plate X. figs. 68-70.) 
Female, length 4^, breadth 444”. 
External Characters—Body white, tapering forwards and also towards posterior ex 
tremity, which terminates in a sharp point. Head truncate. Integument with trans 
verse strive, 55555 apart; longitudinal not seen. 
Pharyngeal cavity zoog" long. Œsophagus about Hh of total length. Intestine 
covered with few but large and dark-coloured hepatic granules. Anus gpg” from por 
terior extremity. Vulva slightly posterior to middle of body. 
Male, length 3", breadth 959 - 
` Anus yiz” from posterior extremity. Spicules double, 45” long, united to a post- 
