142 MESSRS. ALDER AND HANCOCK ON 



or posterior tube passes from the under side of the stomach immediately behind the 

 oesophagus, and runs backwards, passing below the ovary, to the posterior portion of 

 this substance on either side. The papillary glands are simple, or perhaps a little foUi- 

 culated ; they originate in this glandular matter, and are very short, extending only into 

 the base of the papillae. 



The reproductive organs agree, as far as they were examined, with those of Antiopa ; 

 and the nervous centres appear to be similar to those of that form. 



This genus evidently belongs to the family Proctonotidse ; but it has become necessary 

 to extend the previous characters of the family to include it, as it differs from the other 

 members of the group in the lateral position of the anus, and the absence of oral ten- 

 tacles, unless the veil-like expansion of the head be so considered. 



Madrella ferruginosa, n. sp. (PI. XXXIII. figs. 10, 11, 12.) 



Body elongate wedge-shaped, or sharply ovate, depressed, broad in front, and tapering 

 to a point behind ; of a deep rusty-brown colour. Cloak much produced at the sides 

 and in front, nearly covering the head and foot, excepting posteriorly, where the latter 

 extends into a pointed tail, carinated above. Branchial papillae linear, tapering to a 

 fine point, placed three or four deep round the margin of the cloak, extending round the 

 head in front of the tentacles and meeting behind, so as to form a continuous belt, 

 leaving a bare space in the centre of the back, where there are a few scattered tubercles : 

 the papillae are of moderate size, becoming small towards the margin of the cloak ; they 

 are hyaline, minutely freckled with brown, and with opake tips, the gland, which is 

 simple and of a brown colour, passing a short way up. Dorsal tentacles placed near 

 together, and rather backward in position : they are clavate and bent backwards above ; 

 the footstalk longer than the clavate portion, which consists of a belt of numerous simple 

 papillae surrounding a well-developed obtuse mucro. Head expanded into a large 

 broadly arched veil, the lateral angles of which are free. Foot large, broad, and slightly 

 arched in front, without laminae, extending to a point behind. Length nearly 1^ inch. 



Tolerably frequent. Several specimens in good order were in the collection. 



• - Family GLAUCID^E, Alder &i Hancock. 



Genus Glaucus, Forster. 



Body elongate, without cloak. Tentacles four, linear, non-retractile. Branchiae 

 linear, flattened, and tapering, arranged in fan-like pedunculated tufts on the sides of 

 the back. Anus lateral. Foot narrow. Tongue a single longitudinal series of arched 

 plates, with a central spine and lateral denticles. 



