j.62 ECHINOIDEA. I. 



The greatest depth hitherto given for Ech. csculcntus is no fathoms. Now it has been taken 

 by the <-Ingolf on 310 and 691 fathoms. Certainly, however, it is not common on so great depths; 

 it properly belongs to the littoral zone. 



This species is not very varying. A peculiar form with especially fine spines and high test is 

 by Norman') denoted as var. tenuispina; it seems only to occur on greater depths. Hoyle further 

 establishes a couple of varieties: . with red test and spines, and /9. with brownish-red spines 

 (op. cit. p. 412), there is, however, I suppose, only slight reason to distinguish that kind of colour- 

 varieties. A couple of specimens of a middle size from the North Sea (40 fathoms) found in the col- 

 lection of our museum, have a very peculiar appearance, being very similar to Ech. clcgans. The 

 spines are uncommonly long and quite red, and the test not so high as usual. But the spines on the 

 buccal plates and the fact that only every other ambulacral plate has a primary tubercle, leave no 

 doubt of their being esculentus. These specimens perhaps correspond to Hoyle's var. . A couple of 

 larger, naked tests from Norway, also found in the museum of Copenhagen, combine to a curious 

 degree the characters of both E. esculenttts and acutus, var. Flemingii, so that it is quite impossible 

 to decide with certainty to which of these species they belong, and the supposition of their being 

 hybrids between the two species seems very obvious. 



It seems that the species Ech. Schioartzii described by Nilsson & Hoist, can be no other 

 thing than a young E. esculentus; there is nothing in the description that will not agree with this 

 species, and other Echinids with red test are not found at the Norwegian coast on the rocks at the 

 very edge of the water; otherwise the type specimen is no longer found in the museum of Lund. 



Fam. Toxopneustidae. 



Subfam. Strongylocentrotinse. 



17. Strongylocentrotus drobachiensis (O. F. Mull.). 



PI. I. Figs. 5-6. PI. II. Figs. 35. PI. XVI. Figs. 4, 9, n, 13, 17, 21, 23. PI. XX. Figs. 3-6, 12 13, i 6 . '8, 20, 2526, 29. 

 Principal synonyms: Echinus neglectus Lamk. 



granularis Say. 

 granulatus Gould. 

 Toxopneustes pictus Norman. 



pallidus G. O. Sars. 



Principal literature: Dtiben & Koren: Ofvers. Skand. Ech. p. 277. Liitken: Oversigt over 

 Gronlands Echinodermata. 1857. p. 24. -- G. O. Sars: Nye Ech. fra den norske Kyst Forh. Vidensk. 

 Selsk. Christiania 1871. p. 25. -- Agassiz: Revision of Echini, p. 277. -- Duncan & Sladen: Mem. 

 Ech. Artie Sea (135). p. 19. - - Hoyle: Revised List of Brit. Echinoidea (202). p. 408. Bell: Catalogue 

 of Brit. Echinoderms. p. 156. 



') On the Crustacea, Tunicata, Polyzoa, Echinodermata, Actinozoa, Hydrozoa and Porifera. Shetland Final Dredging 

 Report. II. Rep. Brit. Assoc. 1868. p. 314. 



