356 THE FUR SEALS OF THE PEIBILOF ISLANDS. 



"have been able to glean from the literature, the collections in the United States 

 National Museum, and from the naturalists who have visited the group in recent 

 years. I have attempted to give a full measure of credit in all cases, with reference 

 to the actual specimens when any are known to exist. Nearly all of these I have 

 seen. The chapters on Migration and Distribution seem pertinent to an understanding 

 of the avifauna of these islands and are offered as suggestive for future work in the 

 region. 



As to the systematic arrangement, I must confess my responsibility. I have 

 begun the list with what appears to me the lowest and most generalized type — the 

 cormorant. Not only upon general physiological grounds, but uxJon the purely 

 morphological one of the nature and development of the feathers have I considered 

 this group the lowest of the birds given in the list. At the other extreme, the higher 

 and more specialized, I have placed the Fringillidre. Several reasons might be 

 advanced for this, but the following may suffice here: As in botanical science the 

 Spermatophyta are, geologically and chronologically speaking, the higher and most 

 recent, so in birds the seed eaters and their allies are necessarily, in point of time, 

 the most recent, and as a group more highly specialized. In an evolutional sense 

 they have kept pace with the general development of the higher botanical groups, 

 even specializing to a very high degree in their food-getting habits. If the vegetation 

 of the world had never advanced beyond a pteridophytan stage, it is difficult to 

 imagine the development of the Oonirostres; nevertheless the insectivorous birds 

 would have beeu prominent. The arrangement in such a small list of the intermediate 

 groups is not so satisfactory. The valne of the purely nonfunctional and almost non- 

 adaptive characters of the neossoptiles^ and mesoptiles,' when they are better known 

 and have been comparatively studied, may afibrd a clearer insight into the relation- 

 ships of genetic groups as well as of the lowest members of the various orders. The 

 taxonomic values of the neossoptiles may be indicated as follows : In Phalacrocorax 

 they are almost entirely dissociated externally with the mesoptiles. The rachis is 

 short and weak, and the rami connect with it in an uneven manner. In the Anatidw 

 the rachis is strong and long, and the connection with it of the rami is regular. These 

 neossoptiles are carried for a time on the tips of the new growing mesoptiles, either on 

 the flight feathers by a strong connection with the enlarged tip of the rachis of Ihe 

 mesoptile, or on the body feathers on the united tips of the rami and weakened rachis. 

 In all the other groups the neossoptiles divide, have no rachis, and are carried singly 

 on the tips of the rami of the growing mesoptile. In the higher groups this division 

 into single parts is usually prevented by a band formed of a persistent portion of the 

 sheath. Correlated with the above are other conditions, sucli as the condition at 

 hatching, the duration of growth or nongrowth either of these feather structures or 

 of the basal portion of the neossoptile, the period and time of further changes, etc. 



There is no consistent practice concerning the use of the comma between the 

 speciiic part of a name and the name of the authority or oiter. I have used the 

 comma only to indicate the fact that the author following is the user and not the 

 authority or original describer. 



To Mr. Eobert Eidgway and Dr. 0. W. Eichmond, curator and assistant curator 

 of the Department of Birds of the National Museum, my thanks are due for many 

 courtesies in connection with examining the specimens and literature. To Mr. P. A. 



■ Pago 424. 



