TO BIRD-ANATOMY AND CLASSIFICATION. 207 



into a considerable conical hair-covered process, projecting into the 

 second stomach, and evidently acting as a valve to close the pylorus when 

 necessary." These differences in two species so closely allied in all other 

 points show that, though in nine cases out of ten similarity of external 

 characters predicates similarity of internal structure, nevertheless in 

 the tenth the correspondence breaks down, and that, too, without any 

 obvious differences in mode of life, food, &c. The parallel, pointed out 

 by Prof. Garrod, presented by these two species of Plotus with the two 

 living genera of Sirenia (Manatus and Halicore), as regards the modification 

 of their gastric gland- structures, is particularly interesting. 



10. Coliidce*. The skull of Colius is desmognathous, and has no 

 vomer, as in Alcedo. The viscera and myology do not bear out the idea 

 of any relationship to the Parrots or Musophagidae ; on the contrary, 

 these birds are truly Anomalogonatous, and are most nearly related 

 perhaps to the Alcedinidse and Bucerotidse. Nevertheless their combina- 

 tion of characters fully substantiates their claim to form a separate 

 family, Coliidae. 



11. Thinocoridcet. These birds, in their schizorhinal skull, and in 

 many other features, visceral and myological, resemble most some of the 

 more aberrant forms of Limicoline birds, such as Cursorius and Olareola. 

 Attention is also drawn in this paper to the very extensive variations in 

 the form of the vomer in various Charadriiform birds, it being (so far 

 from always " tapering to a point anteriorly," as it should [?] do in these 

 " schizognathous " birds) in several forms extraordinarily broad or even 

 widely emarginate anteriorly ! 



12. Momotidce $. The colic caeca being absent, at the same time that, ibi a , 1881, 

 except in Momotus, the oil-gland is tufted, the Momotidae must be placed P- 25- 

 amongst the Piciform series of Anomalogonatae, close to the Todidae, and 



not with the Coraciidae amongst the Pas serif ormes. The syrinx and some 

 other points in their anatomy are also described. 



13. Megacephalon . A short paper describing the pterylosis (hitherto 

 almost unknown in the Megapodidae), syrinx, and other points in this 

 peculiar form, which is perfectly gallinaceous. 



14. Indicator \\. In its pterylosis, visceral anatomy, myology, and 

 osteology, Indicator closely approaches the Picidae, Capitonidae, and their 

 allies, and is in no respect Cuculine. Its vomer is large and strongly 

 bifurcate anteriorly, as in the Capitoninae ; of the latter some are 



* " Notes on the Anatomy of the Colies," P. Z. S. 1876, pp. 416-420. 

 t " Notes on the Anatomy and Systematic Position of the Genera Thinocorus and 

 Attagis? P. Z. S. 1877, pp. 413-418. 



\ " On the Systematic Position of the Momotidae," P. Z. S. 1878, pp. 100-102. 



" On the Anatomy of the Maleo," P. Z. S. 1878, pp. 629-631. 



II " Notes on the Anatomy of Indicator major," P. Z. S. 1878, pp. 930-935. 



