248 P. W. GAMBLE, B.SC. 



author probably mistook the sucker for the pore. The vasa deferentia 

 are scarcely so swollen as in 0. sanguinolentus, and the vesicula semi- 

 nalis rather larger than in the latter. The granule gland and copu- 

 latory organ agree exactly in both species. Claparede figures large 

 rounded bodies which may possibly prove to be the accessory uterine 

 glands (Lang). 



Habitat. — On Laminaria, Lamlash Bay, Arran (Claparede). 



A more exact description of this species is necessary before the 

 specific identity or difference of Oligocladus sanguinolentus and auritus 

 can be regarded as proved. It appears fairly clear that they both 

 possess the same generic characters — the subterminal mouth, position 

 of the genital pores, and multiple uterine glands. No satisfactory 

 points of difference can at present be determined. On the contrary, 

 it is noticeable that it is just those organs which Claparede describes 

 accurately — the mouth, pharynx, and intestine, and the male copulatory 

 organ — which agree exactly with the corresponding structures in 

 0. sanguinolentus. 



Genus 34. — Stylostomum, Lang (1884). 



Body smooth. Tentacles rudimentary. Oral and genital apertures 

 open on a common depression immediately behind the brain. Main- 

 gut with 5 — 6 pairs of secondary non-anastomosing branches. The 

 median anterior branch is absent over the pharyngeal region. Male 

 copulatory organ lies under the anterior part, the female organ under 

 and behind the hinder part of the pharyngeal sheath. Two uterine 

 glands. Cephalic eyes few in number. 



71. Stylostomum variabile, Lang. PL X, fig. 1. 



? 1853. Planaria ellipsis, Dalyell (29). 



? 1865. Leptoplana ellipsis, Johnston (38). 

 ? 1875. „ „ Mcintosh (45). 



1884. Stylostomum variabile, Lang (54). 



1884. Stylostomum? ellipsis, Lang (54). 



Length 5 — 9 mm. Body elliptical, broadly rounded behind, tapering 

 slightly in front. The extreme anterior margin truncate. Tentacles 

 more conspicuous in adults than in young specimens, where they form 

 mere blunt marginal projections. Immature specimens derive their 

 coloration from the white or yellowish-white ground-tint and from the 



