544 ME. F. B. BEDDABl) OK THE [-Apr. 21, 



reproduce one or two of Ihe late Mr. Forbes's sketches in illus- 

 tration of the tensores of those birds, which have been but little 

 described. The simplest foim perhaps is to be seen in Synthlibo- 

 rham]}lius antiqims. Here (fig. 3) there is but one tendon to the 



Kg. 3. 



Tensores patagii of Synthlihorhamphus antiquus. 



a, slip to ulnar side of forearm. 



(From a MS. sketch by the late Mr. Forbes.) 



brevis muscle, which is inserted on to the forearm and passes 

 over its muscles to be attached below to the ulna. This single 

 tendon appears to correspond to the anterior of the two invariably 

 present in Gulls and Limicoline birds : this is to be inferred from 

 the fact that it gives off just the merest apology for the wristward 

 branch found in those birds ; there is no patagial fan connecting 

 this tendon with the longus tendon ; but a thin tendon runs from 

 the longus and is attached to the flexor side of the forearm. 

 Purbringer's iigure of these tendons in Aha tarda shows no trace 

 of this peculiar slip ; but it seems to occur at least in the majority 

 of the Alcida3. Its presence and the rudimentary character of the 

 wristward branch of the main tendon of the brevis are the special 

 peculiarities of the patagial tendons in the Alcidje. There are, 

 however, as many as three separate tendons all running parallel in 

 some species. In Lunda (see fig. 4), Ceratorhina (fig. 5), Brachy- 

 rhampJms, and Uria this is the case. In Frateroula and Alca 

 there are only two. In a few species (in Pratercida for instance) 

 where there is a patagial fan, a small ossicle as in the Petrels is 

 developed. It seems clear, therefore, that the patagial muscles of 

 the AlcidsB do not on the whole favour the close relationship of the 

 Alcidoe to any other liimieoline bii'ds, the resemblance to the Gull^ 



