Laomedea. Z. HYDROIDA. 153 



This species, in its most perfect state, rises to the height of 8 or 10 

 inches. The stena is as thick as small twine, straight, opake, and 

 composed of many tubular threads twisted together. It does not 

 properly divide itself, but sends off branches from all sides, which are 

 either opposite or alternate, and much ramified into diverging branch- 

 lets, each of them marked with three or four rings at its base, and 

 terminated with a bell-shaped polype-cell of a very thin corneous 

 texture. A specimen of this description from Shetland, in the col- 

 lection of my friend Dr Coldstream, is figured in Plate XXII I. 



But more commonly Laom. gelatinosa is found in a much hum- 

 bler condition, and under a guise that requires for its discrimination 

 from Laom. geniculata, a careful examination. It occurs thus in 

 Berwick Bay, growing gregariously on the sides and under surface of 

 stones lying in shallow pools between tide-marks, and seemingly 

 giving a preference to those that contain an impure or brackish 

 water. The shoots are all connected with one another by the ra- 

 dicle fibre which creeps in an irregular manner along the rock ; they 

 are rarely above an inch in height, simple or sparingly branched, 

 consisting of a single tube of a light corneous colour and texture, 

 ringed above the origins of the long twisted filiform pedicles on which 

 the polype-cells are raised. These cells are deeply cupped, transparent, 

 with a wide even margin. Vesicles urn-shaped, smooth, shooting 

 from the axils of the pedicles. They are matured during the 

 summer months, when we find them filled with ova of a circular flat- 

 tish form, marked with a dark speck in the centre. At first they fill 

 not more than half of the vesicle, but by their increase in size they soon 

 come to occupy the whole cavity, and are ultimately extruded from the 

 top, after which the empty vesicle soon disappears. The ova while 

 in the vesicle are ai'ranged round a central placentular column, and 

 the lid which closes the vesicle is a mere dilatation of this column, 

 which appears to be composed of two pieces soldei'ed together, and 

 bulged at intervals, where perhaps the ova are more immediately af- 

 fixed in their immature state. 



The Polypes have about twenty long filiform tentacula roughened 

 with minute tubercles placed in whorls. In their centre is the mouth, 

 which assumes the shape sometimes of a rounded projecting tubercle, 

 sometimes of a narrow column, and sometimes of a broad flat disk 

 with a stricture under it simulating a neck. It leads directly to the 

 stomachal cavity which is large and undivided, and I have occasional- 

 ly witnessed within it currents of a fluid filled with minute granules, 

 as has been more fully noticed by Mr Lister and Dr Fleming. 



Milne-Edwards, in the belief of there being a specific difference 

 between the zoophytes described by Pallas and Fleming, has propos- 



