NOTES ON SOME SCOTTISH ECHINODERMATA 49 



NOTES ON SOME SCOTTISH ECHINODERMATA. 



By THOMAS SCOTT, F.L.S., 

 Naturalist to the Fishery Board for Scotland. 



PLATE II. 

 I. On a Depressed Form of Echinus esculentus, Linn. 



A MORE than usually depressed form of Echinus esculentus 

 was obtained in the Firth of Forth in June last (1891), which 

 it may be of interest to notice. There is, as is well known 

 to students of the Echinodermata, considerable variation in 

 in the form of this species, but the variety now under con- 

 sideration is the most depressed of the numerous specimens 

 I have observed among the captures made during several years' 

 trawling on the east coast of Scotland. In form it approaches 

 very closely to Strongylocentrotus drobacJiiensis, M tiller, a 

 species which we have obtained on one or two occasions in 

 the vicinity of Inchkeith, a little east of the south end of the 

 the island, 1 but is to be distinguished at once by the posses- 

 sion of three pairs of pores in the row instead of four or five 

 pairs as in Strongylocentrotus. This variety is represented -f- 

 the natural size on Plate II. Fig. i, and measures 4.65 inches 

 in diameter, and 2.3 inches in height. Fig. 2 represents 

 another variety of the same species with somewhat flattened 

 sides, which was obtained off Musselburgh at from five to 

 six fathoms. Fig. 3 gives us a specimen of the usual form, 

 both natural size. These latter figures show by comparison 

 more clearly the unusual form of the variety under con- 

 sideration : they, also, are represented | of their natural size. 



II. On Goniaster phrygianus (Pardius) = Goniaster equestris, 



Agassiz. 



During the last few years I have obtained two specimens 

 of a Goniaster from the Firth of Forth which closely 

 resemble each other in form, but which differ considerably 

 from specimens of Goniaster phrygianus taken in the Moray 



1 Strongylocentrotus drobachiensis is common in the Cromarty Firth, and we 

 almost invariably obtain a number of specimens of this species every time we 

 trawl between Cromarty and Invergordon. 



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