24 Mr. W. A. Forbes on the late Professor GarrocFs 



organ^ as in some other bircls^ assumes the form of two sepa- 

 rate patches. The second (pyloric) compartment of the 

 stomach is also present, in a well-developed form, and is also 

 hair-clad. But here another diflFerence presents itself; for 

 '' the hairy epithelium surrounding the pyloric orifice .... 

 is produced into a considerable conical hair-covered process, 

 projecting into the second stomach, aud evidently acting as 

 a valve to close the pylorus when necessary .^^ These differ- 

 ences 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, never- 

 theless 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, pre- 

 sented 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 Coitus 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 

 Musophagidse ; on the contrary, these birds are truly Anoma- 

 logonatous, and are most nearly related perhaps to the Alce- 

 dinidse and Bucerotidse. Nevertheless their combination of 

 characters fully substantiates their claim to form a separate 

 family, Coliidse. 



1 1 . Thinocoridcef. — 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 Glareola. 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 extraor- 

 dinarily broad or even widely emarginate anteriorly ! 



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

 V -j- " Notes on the Anatomy and Systematic Position of the Genera 

 Thmocorus and Attagis;' P. Z. S. 1877, pp, 413-418. 



