296 L. K, CRAWS HAY. 



CtENERAL remaeks. 



The most marked feature of the fauna of this outer area of the 

 Channel is its close conformity in the main with that of the Plymouth 

 neighbourhood. Regarding the latter as the area enclosed by a line 

 passing from Start Point to the Eddystone Lighthouse and thence to 

 Looe Island, the fauna of the outer area may be compared with that 

 of the Plymouth neighbourhood under three heads, concerning (1) 

 species common to both areas, (2) species occurring in the Plymouth 

 area which are absent from the outer area, (3) species occurring in the 

 outer area which are absent from the Plymouth area. 



(1) By far the greater bulk of the material comes within this 

 category. With the exception of those that can scarcely be considered 

 among the commoner species, and which are therefore less often met 

 with generally, and excluding strictly littoral species, the majority of 

 the species were found extending with more or less frequency over the 

 whole area. Reference here then will only be made to those more 

 familiar species the limited records of which seem to point to a limit 

 of distribution, or to species which call for special remark in other 

 ways. Distances where mentioned are from the Eddystone Lighthouse, 

 and roughly to the south-westward in direction. 



PoRiFERA. Clathrina coriacca was only once recorded. The species, 

 usually of littoral habitat, gives place at about 18 miles to forms 

 which I have referred to Clathrina primordialis. One of the latter 

 approximates closely in spiculation to C. coriacea, and great as is the 

 difference of spiculation between the two extremes, I am bound to 

 admit a certain doubt as to whether a gradual transition may not 

 prove to exist between them associated with a difference of habitat, 

 in one and the same species. 



Leucosolenia complicata, though occurring nearly everywhere, was 

 remarkable for its slender, straggling habit of growth, possibly due to 

 a lack of proper food-supply. 



Sycon ciliatum was only obtained at two closely approximate 

 positions about 22 miles distant. Outside this, the only closely 

 allied species was the southern species, Grantia capillosa, which was 

 obtained as close in as the first position, 8 miles distant. The latter 

 species certainly also occurs near or even inside the Eddystone, though 

 the few Plymouth specimens in the Laboratory Museum are without 

 data of locality. 



Leucandra Jistulosa, generally distributed in the Sound, only once 

 occurred at the first position, 8 miles distant. 



Polymastia mammillaris, common at certain points on rocky ground 



