42 



PROCEEDENGS OF THE NATIONAL MUSEUM 



&SSy^ 



mmn 



Figure 4. — Henricia scabrior: a, lateral ray plates; h, aboral ray spines; c, lateral ray 

 plates; d and e, adambulacral spines. 



The most variable features of the species are the arrangement 

 of the plates on the side of the ray adjacent to the adambulacrals 

 and the adambulacral spines. Frequently 1 or 2 longitudinal rows 

 of plates occur fairly regularly along the ventrolateral surface of 

 of the ray, parallel to the adambulacral plates. Dorsal to these, 

 quite uTegular papular spaces are enclosed by a variable arrange- 

 ment of plates, and occasionally single isolated plates occur within 

 the papular areas (figs. 4a,c). Adambulacral spines are frequently 

 present as a single row of about 6 per plate (fig. 4e), but may be 

 more numerous (up to 12 per plate), may occur in an irregular zig- 

 zag pattern, and may often resemble 2 rows per plate (fig. ^d). 

 Both patterns may occm- in single individuals. Dorsally, a membrane 

 characteristically covers single spines per plate, but there may be at 

 least 4 per plate. Spines lack the terminal crown of points char- 

 acteristic of H. eschrichti; lateral ridges do not extend higlier than the 

 central portion of the spine (fig. 46). One specimen with excep- 

 tionally slender rays showed unusually small papular areas and 

 relatively more slender spines than do other individuals. 



Specimens were collected (fig. 1) from Nain to Hamilton Inlet; 

 these are the first published records of the species from Canadian 

 waters. With a temperature range of nearly —1.8° to 1° C and 

 a sahnity range of 32 to nearly 33 (fig. 2), the species is hmited here 

 to an environment of high salinity, and relatively low temperature. It 



