256 Prof. P. M. Duncan on the Salenidse. 



with its crowd of processes, and . tlie similar bodies on the 

 plates. They are more pronounced than in Salenia profundi^ 

 less close, but identical in structure ; they are not rudimen- 

 tary spines. The form is a true Salenia ; and the ovoid anus 

 is eccentric, posterior, and to the right. The large size of the 

 right and left and posterior plates is remarkable, and, with 

 the difference of the ornamentation and the number of papillse, 

 distinguishes the species, partly, from Salenia profundi. 



In concluding this part of this essay it is necessary to point 

 out the specific characters of Salenia profundi. 



Salenia profundi, sp. nov. (PI. VII. figs. 1-11.) 



The test is depressed, the inferior surface being flat and the 

 upper slightly convex. The greater part of the upper surface 

 is occupied by the apical system ; the peristomial space is 

 large, and the rest of the test is crowded with tubercles and 

 their spines. There are ten primary tubercles (some very large 

 and some small) in the two vertical rows in each interambula- 

 crum ; their spines are of different lengths, some more than four 

 times the diameter of the test, others less, and some very short 

 and conical. The longer spines, often slightly bent, are pin- 

 shaped, with a large milled ring and a constriction beyond. 

 There are two vertical rows of secondary tubercles in the 

 median interambulacral spaces, and one row between the 

 primary tubercles and the poriferous zone. All these have 

 short club-shaped, straight or curved or broad spatula-shaped 

 spines, striated and pigmented. 



The ambulacra are narrow, and there are two vertical rows 

 of tubercles closely packed, just within the poriferous zones ; 

 and their spines resemble those of the small tubercles of the 

 interambulacra. Other tubercles near tlie peristome support 

 cylindrical spinulose spines ; all are ornamented with pigment 

 granules. The pores are few in number, in simple series, a 

 pair corresponding with each tubercle. Pedicellariai are 

 amongst the spines, and are short and blunt-headed and bifid. 



Sphajridia exist, two close to the peristome and one Iiigher 

 up in each ambulacrum. 



The surface of the test is pigmented with dots and granules 

 of dark purple. There are ten buccal plates, the opening for 

 the teeth (actinostome) is small. Teeth triangular and slightly 

 keeled ; buccal membrane plain, and only slightly imbricated 

 near the teeth. 



Cuts slight ; branchiae bifid or trifid. Pedicellarije in pairs 

 near the buccal tentacles. 



The anus, with a raised margin, is eccentric posteriorly and 



