254 Proceedings of the 



1. Laomedea acuminata. 



A beautiful zoophyte was discovered by Mr Alder, and de- 

 scribed by him in the last December number of the " Annals of 

 Nat. Hist.," under the title of Laomedea acuminata, which I 

 am disposed to consider identical with the subject of this notice. 

 It has been familiar to me since March last, when I found an 

 old pecten shell in one of the tanks of my friend Dr Paterson 

 of Leith, covered with its flower-like polyps. In May it was 

 dredged up on an old oyster shell from the Frith of Forth, and 

 sketched by myself and Dr Mackay ; and in August, a fine 

 specimen occurred on a living oyster in the vivarium of the 

 Edinburgh Zoological Gardens, which has been domesticated 

 with me ever since, and which I place on the table to-night. 

 Mr Alder describes it thus : " Laomedea acuminata— Pol j- 

 pary minute, scarcely branched, with a slender annulated 

 stem ; cells thin, membranous, finely striated longitudinally, 

 elongo-ovate or pod-shaped, squared below and tapering to a 

 fine point above ; margin slightly crenulated ; polyp reaching, 

 when extended, to two or three times the length of the cell, 

 with about twenty muricated tentacles. '' He remarked, also, 

 that the tentacles were united by a web for about one-sixth of 

 their length, which he has well shown in his figure of the polyp. 

 In all the specimens in my possession the tentacles, instead of 

 being erected as in Mr Alder's figure, were alternately erected 

 and depressed (Plate XIII., fig. 1, a), as they reached the top 

 of the membranous funnel which united their bases together. 



The distinguished discoverer of this Zoophyte found much 

 difficulty in ascertaining the true shape of the margin of the 

 cell, on account of its exceedingly thin and membranous tex- 

 ture. This membrane, however, appears to me to be an addi- 

 tional softer structure, which incloses the cell proper, and, 

 projecting beyond the mouth, falls twisting together when the 

 polyp retires within its cell. Old cells, accordingly, which 

 have long lost their tenants, are destitute of this membrane, and 

 present an even rim like old cells of Campanularia syringa. 

 In my specimens, moreover, the cells were inclined to their 

 annulated stems. The long lax tentacles were muricated with 

 small thread-cells, while the inner surface of the membranous 



