298 L. E. CEAAVSHAY. 



fluences the manner of growth where the latter is variable. Yet the 

 seeming scantiness of the Hydroid fauna over most of the outer area, 

 coupled with the frequent records of small colonies, and distinctly 

 dwarfed colonies in the case of P. setacca point to conditions that are 

 unfavourable to healthy growth in the group. 



EcHiNODEEMATA. Palmipcs 2}l((ccnta was not found outside the 17- 

 mile point, and at the latter only as small specimens. 



Echinus acutus was not recorded inside a distance of 15 miles, which 

 is about the inner limit of the stony ground. E. esculcntus, on the 

 other hand, occurred over the whole area, and in considerably greater 

 numbers. 



PoLYCHAETA. The outcr limit of occurrence of Aphrodita aculeata 

 was at 20 miles ; that of the nearly allied Hermione hystrix extended 

 to 46 miles. The latter species seems generally to favour grounds of 

 a coarse character. 



Halosydna gelatinosa occurred only at 39 miles. 



Onuphis conchiler/a was not found beyond the 26-mile point. 



Ceustacea. Fortunus dcpurator, often an abundant species in the 

 Sound, and found abundantly by Dr. Allen (1) 3 miles east of the 

 Eddystone, was only once obtained at 17 miles. 



Atelecydus septtenuhnUdus has been recorded from as much as 100 

 fath. and even 400 fath. (cf. Allen, 1), but in the area here considered 

 it was not found beyond 30 miles. This species is scarcely likely to 

 have been much missed in the work owing to the constant use of the 

 dredges with a special view to deep working. Allen considers that a 

 certain amount of muddy deposit contributes to the most favourable 

 conditions for the species, and it is possible that the almost entire 

 absence of any such deposit on the outer grounds may explain its in- 

 frequency and even disappearance at the more distant positions visited. 



MOLLUSCA. Craspedochilus onyx was not recorded beyond 20 miles. 



Capulus hungaricus, taken on five grounds by Dr. Allen between 

 Start Point and the Eddystone, at 30 fathoms, was not found alive in 

 the area here under consideration, though dead shells occurred as far 

 out as 27 miles. 



Of Fecten maximus there is a noticeable scarcity at all points as 

 contrasted with F. opcrcularis, which was at times abundant. About 

 five living specimens were obtained at three positions, all situated 

 about 20 miles out. At other positions from one to three only 

 occurred, and the total number obtained probably did not exceed forty. 

 On the grounds near the Eddystone it was found by Dr. Allen with 

 much greater frequency, two or three specimens being generally taken 

 in each haul with the dredse. 



