248 Prof. P. M. Duncan on the Salenidge. 



The ends of the teeth are closely applied to each other, and 

 there is no space between their visible sides in the solitary 

 specimen ; they are bluntly and broadly keeled externally and 

 have angular ends. 



No mention is made by Lovdn of the buccal membrane of 

 Salenia Goesiana ; but A. Agassiz writes as follows regarding 

 that of Peltastes varispina : — " The imbricated buccal mem- 

 brane is covered thickly with plates arranged somewhat as _ 

 they are in Echinocidaris. Tlie ten buccal plates placed half- 

 way between test and teeth are sparingly covered with pedi- 

 celiarige " [op. cit. p. 261). In Salenia profundi the imbrica- 

 tion is of the faintest close to the actinostomial opening, and 

 does not exist elsewhere, and no plates are visible ; but 

 as Echinocidaris =- Arhacia^ in which genus the buccal mem- 

 brane is bare, it is probable that there is no great amount of 

 imbrication in the interesting specimen described by A. 

 Agassiz. The actinal cuts are small in the three recent 

 Salenidse. 



Most of the spines being in place in the specimen of 

 Salenia profundi^ only a few tubercles can be examined ; but 

 they are invariably, whether in the interambulacra or in the 

 ambulacra, imperforate. The large primary tubercles of the 

 interambulacra have large bosses ; and their crenulation 

 resembles a circular series of nodules around their bases. 

 This appearance, differing from the usual crenulation, is shown 

 to exist in Salenia Goesiana by the help of Lov^n's magnifi- 

 cent delineation (Lov^n, '■ £^tudes,' pi. xix. fig. 164). It differs 

 from that drawn by A. Agassiz. 



No crenulation is found around the ambulacral tubercles in 

 the two species of Salenia ; but the following quotation from 

 the ^ Revision of the Echini'' makes it doubtful whether it is not 

 found in the varispine species : — " The primary tubercles of 

 both areas are imperforate, hut distinctly cremdatedy A care- 

 ful examination of the plate in illustration does not satisfy the 

 eye that there is crenulation in the ambulacra. 



The number of the tubercles in the interambulacra of 

 Salenia profundi and Salenia Goesiana is not more than ten, 

 counting all of both rows ; but, although A. Agassiz does not 

 give the number, it is evident from his drawings that there 

 are more than ten in his species. It must be remarked that 

 the size of the specimen described by A. Agassiz is larger 

 than that of the other two forms, and that the increased num- 

 ber of tubercles may be a matter of growth. It is impossible, 

 however, to restrict the number of coronal plates to a "few," 

 or the number of principal tubercles to ten in the genus 

 Salenia (see ' Revision oi Echini ^^ p. 258); for in the Australian 



