174 ANATOMY AND PHYSIOLOGY 



clrus. Fig. 355, Plate XXVIII, represents a view of a 

 section at right angles to the surface exhibiting the radial 

 fasciculi of the peripheral system with the ternate apices of 

 the spicula immediately beneath the dermal membrane 

 X 50 linear. 



We have no British species of this genus ; the type 

 species, Ecionemia acervus, Bowerbank, MS., is in the 

 Museum of the Royal College of Surgeons of London. 



ALCYONCELLUM, Quo?/ et Gaimard (Euplectctta, Owen). 



Professor Owen, in his paper on Euplectella aspergillum, 

 Owen, communicated to the Zoological Society January 

 26, 1841, and published in the ' Transactions of the Zoolo- 

 gical Society of London,' vol. iii, part 2, p. 203, pi. xiii, 

 appears to have fallen into a singular number of errors in 

 the course of his description of this beautiful sponge. He 

 has, in the first place, designated it as belonging to the 

 Alcyonoid family, apparently only because it is cylindrical 

 in form and reticulate in structure, but without the 

 slightest reference to the polyps that must necessarily cha- 

 racterise an Alcyonium ; and he proceeds in his descrip- 

 tion to describe the base of the sponge as its apex and the 

 apex as its base. The author then notices the first speci- 

 men of this genus that was made known to us by MM. 

 Quoy and Gaimard, in the ' Zoologie de 1 J Astrolabe/ Svo, 



1833, p. 302, planches fol. Zoophytes, fig. 3, pi. xxvi, 

 but unfortunately mistakes the generic name Alci/onceJlmn, 

 applied to the sponge by the French authors, for Alcyonel- 

 lum ; and having mistaken its name, its base, and its apex, 

 he proceeds to reason on its generic characters thus : " If 

 the basal aperture of the cone were open, the resemblance 

 to some of the known reticulate Alcyonoid sponges would 

 be very close, especially to that called Alcyonellum gela- 

 tinosum by M. de Blainville, ' Manuel d'Actinologie/ Svo, 



1834, p. 529 (Alcyonellum speciosum, Quoy et Gaimard): 

 its closure by the reticulate convex frilled cap, in the pre- 

 sent instance, establishes the generic distinction ; and in 



