338 L. E, CKAWSHAY. 



(twenty, and two young), 51 (one)' 52 (five), 53 (three), 56 (one) 

 58 (one young), 59 (one young), 66 (thirteen), 67 (two), 68 (eight), 

 70 (few), 72 (few), 78 (eleven), 80. 



Depth, 40-52 fath. 



The total number recorded is about 120, as opposed to about 

 15 of the preceding species. In his Eeport on the fauna between 

 the Eddystone Grounds and Start Point, Dr. Allen (1) discusses 

 in detail the conditions influencing the distribution of these 

 two species. In regard to the great numerical difference between 

 them in the area now dealt with, it is probable that Dr. Allen's 

 remarks on the bare survival of acutus in the Plymouth area 

 as being on the outskirts of the deep-water area, where it 

 abounds, are directly applicable to the present case, since the deepest 

 positions now under consideration extend very little beyond the 

 50-fathom sounding. It is this line that apparently marks the inner 

 limits of the conditions especially favourable to the species, and its 

 non-occurrence in the few hauls that were made near that depth may 

 be due to local conditions. 



In a recently published number of this Journal, Shearer, De Morgan, 

 and Fuchs* express a difficulty in distinguishing many specimens of 

 acutus and csculcntus from one another, and even a doubt as to their 

 true specific distinction. As regards specimens here recorded, no 

 such confusion between the two forms as separated was noticeable, 

 though in most cases where acutus was found the two species occurred 

 together. 



Echinus miliaris, Linnaeus. 



A single specimen was obtained at each of the positions 1 and 80. 

 Depth, 40-51 fath. 



CLYPEASTRIDAE. 

 Echinocyamus pusillus (0. F. Miiller). 



At Positions 1 (several), 45 (a few), 56 (one). 

 Depth, 40-49 fath. 



Spatangus purpureas, 0. F. Miiller. 



Large specimens at Positions 5, 9, 10, 11, 74 (one each), and 67 (two). 

 Medium-sized specimens at Position 46 (a few). 

 Small or young specimens at Positions 5 (a few), 17 (one), 20 (one), 

 31 (a few), 36 (one), 46 (several), 51 (a few), 56 (one), 58 (several). 

 Depth, 40-49 fath. 



* " Preliminary Notice on the Experimental Hybridization of Echinoids," Journ. Mar, 

 Biol. Assoc, N.S., Vol. IX, 1911. 



