414 TROF. J. A. THOMSON AND MK. W. 1). HENDERSON ON [Apr. 10, 



As this seems to be a varial)le species, we add a few notes in 

 i-egai-d to othei' specimens : — 



(a) The colour of some when alive was blue all over; the colour 



of the presei'ved specimens may show a tint of green or 

 may be pure white. 



(b) The size of the lai-ger zooids is variable, e. y. in length and 



breadth in millims. 20 x 2-5, 15 x 2, 7 x 1-5. 



(c) No importance need be attached to cases wheie there seem 



to be five pinnules abi-ea«t on one side of a tentacle, since 

 these trivial deviations occur in colonies where the normal 

 number of four rows is thoroughly dominant. 



(d) Another set of specimens was marked by the following 



peculiarities : — (1) Somewhat slender stalks, 17-25 mm. in 

 height, rise from a flat spreading membrane. (2) The 

 pinnules, which are mostly absent, seem to have Ijeen 

 decidedly shorter than the normal, a deviation which is 

 also noted by May ; but it is diilicadt to say how much of 

 this is purely artificial. (3) The -ciilcareous bodies men- 

 tioned by Kcilliker, but not foinid by May, are abundant. 

 They are either spheiical or loundish oval in shape and 

 highly refractive, with a diameter of about O'OOl mm. 

 Some yellowish spherical zoochlorellaj, about 0"36 mm. 

 in diameter, ai-e also present. 

 Locality. Zanzibar Harbour, lowest tide-level. 



Cespitularia ccerulea Miiy. 



(1) A much-branched colony which was, when alive, of "a 

 brilliant sea-green colour, except the iipper faces of the small 

 zooids which wei'e blown." It seems to be referable to May's 

 Cesjfii'idaria cmrulea, which is desci'il)ed, lunvever, as " flesh- 

 coloured with a tinge of bright blue." 



This specimen agrees with May's diagnosis in having 



( 1 ) One I'ow of pinnules on each side of the tentacles ; 



(2) Polyp- bodies about 4 mm. in lengtli ; 



(3) Tentacles about 2'5 mm. in length ; 



(4) No calcareoiis bodies. 



The mode of branching, on the whole, corresponds with May's 

 desci'iption ; but theie is this noteworthy peculiarity, that one 

 division of the colony is sometimes connected with the main mass 

 by a narrow isthmus, e.g. 10 nun. in length by 1 mm. in breadth. 



(2) Another colony I'ises from a flattened base which spreads 

 ovei' a pai't of the surface of a shell, the re,st being covered by a 

 sponge. When alive it was described as having " pink stems 

 with slender brown zooids." The preserved specimen had at first 

 a greenish tinge, which was afterwards lejjlaced by the usual 

 dull creamy white. 



The stalk, which soon branches, is faii'ly fiim in texture, but 

 there are no calcaieous corpuscles. 



Near the base it gives off a small branch which has spread over 



