156 Proceedings of the Royal Physical Society. 
The following table summarises the results of the records given above :— 
eS : aS 
RG ° << J ws | > 
S s 3 S Ss = 
7 = > = 8 is) 
> S S QQ. | 3 
iS = ss 8 n } S 
S iS eS oS Se 3 zs) 
» 5 | Rs ns 3 
| os S > > = 
3 5 | se i SS S 
= S aS = D pS 
Ge o~ = 3 3 < > 
Bo] OS | Se 
| 
| 
| 
| 
11 birds, 6 birds. 6 birds. | 11 birds. | 10 birds. | 1 bird. 
D, acutipectus, Kell. | als Le L x (6) 
| | il 1 
| D. calvus, Kell. . | al x (11) a8 jl x (2) fae Ht x (5) 
D. celedouvus, N. L, | x (2) ( x (6) x (2) o 3 3 
2 J | On 
| D. megacephalus, D. | | | 4 (1)(S) | ie x (11) gine 
| D. mergu, D. . | \ x (1) (S) a | ie A rx (10) as RG 
| I: 
ED ab ! ui| sit Wr || PUES RUBIES 2 DG ie 
Dilieterod see | a x (1)(S) | : 
D. cordiceps, P. | see Hoo | xe ni x (1)(8) 
A x denotes the occurrence of Docophorus on bird sp. The number in brackets 
indicates how often the parasite has occurred on the host species. 
The long brackets with their numbers show how often and how many species have occurred 
together on an wmdividual host. 
(S) = straggler. 
Thus column one reads: “Of Uria trole, 11 birds have been examined and on all 
D. calvus has heen taken, In two cases D, calvus has been found with D. celedoxus, and 
once with D. mergult. The last, however, seems a case of ‘straggling,’” 
1. From the above analysis, it will be seen that each of the five Auks 
found in British waters has a species of Docophorus peculiar to itself within 
that area. 
2. It should not however be inferred that, apart from straggling, there is 
a constant connection between the parasite species and one host species, ¢.g. 
D. acutipectus and F. arctica, ete. Docophorus species as a rule attach themselves 
either to a group of birds, or to a genus, or to near relatives within the same 
genus ; and the fact that we have five auk Docophori in Britain would indicate 
that the hosts represent as many genera. So far as it goes the evidence here 
is for the separation of Cepphus from Uria. Outside British waters the 
Docophori just recorded may be expected on closely allied species of the 
host genera. JD. calvus was described from Uria troile californica (Bay of 
Monterey, California); D. acutipectus from Ceratorhina monocerata (Bay of 
Monterey, California); D. procaz, K.and ©. (which seems to me indistinguish- 
1 On one individual also D. acutipectus and D. celedowus were found associated. 
