•^OJ. Recent Literature. July 



Stone on the Genus Psilorhinus.* — Of the four species described bv 

 authors — P. morio (Wagl.),/^- tnexicantis, Riipp, P. cyauogenvs Sharpe P. 

 Z'oci/eriis (Cabot) — P. cyanogenys Sharpe is referred to P. nicxicanus, the 

 characters oi P. cyanogenys being individual and inconstant; P. -'ociferiis 

 also proves barely separable from P. mexicatttis. The type of/', -oct'feriis 

 is in the collection of the Academy. — J. A. A. 



Professor Thompson on the Systematic Position of Hesperornis. — 

 Among the more recent of the anatomical papers from time to time pub- 

 lished by University College, Dundee, is one by Professor D'Arcy W. 

 Thompson 'On the Systematic Position of Hespcror>/rs,'\ in which the 

 author, after a careful and concise comparison of Hesperornis with 

 Colymbns, sums up as follows : "'It appears to me that from purely osteo- 

 logical characters, the wide differences between Hesperornis and any 

 Ratite, and its close resemblance to Colymhus or to Podiceps is clear and 

 patent." 



The Colymbine affinities of Hesperornis have been dwelt upon at some 

 length by Dr. Fiirbringer: and Dr. Shufeldt, although giving no reasons 

 for his conclusions, has stated his opinion that the Loons and Grebes are 

 derived from the same ancestral stock as that to which Hesperornis be- 

 longed. Professor Thompson seems to have to some extent misunder- 

 stood Dr. Fiirbringer's conclusions, and the latter in a recent paper has 

 felt the necessity of giving full quotations from his ' Morphology ' to 

 showthat ProfessorThompson's views were substantially those previously 

 brought forward by himself. 



We are not quite prepared to accept the statement that the resemblance 

 existing between Hesperornis and Colymbus are " as great as between 

 Strigops^wdi the other Parrots," preferring to hold with Dr. Helm that 

 Hesperornis is an early and highly specialized offshoot from tlie stem of 

 which the Loons and Grebes are later branches. 



In respect to the pelvis, it hardly seems that Professor Thompson or 

 Dr. Helm lay quite enough stress upon the general character of the pelvis 

 and the separation of ilium froin ischium; although, on the other hand, 

 this does not necessarily indicate Struthious affinities, a more exact state- 

 ment of the case, perhaps, would be that the pelvis o{ Hesperornis is of a 

 low, or generalized type, highly modified for swimming. 



There are many interesting points that might be dwelt upon, but space 

 will not permit. 



The many structural resemblances — morphological and pliysiological 

 — between Hesperornis and Colymhus are well brought out, and we think 

 that most ornithologists will agree with Professor Thompson that the 

 proper place for Hesperornis is a long distance from the Ostriches. 



* On the Genus Psilorliinus Riippell. By Witmcr Stone. Pioc. Acad. Xat. Sci. 

 Phila.. 1891, pp. 94-96. 



t Studies from the Museum of Zoology in Universiiy College, Dundee, Vol. I, 

 No. 10. 



