12. PEEIOPHTHALMITS. • 99 



cl. Half-grown. Chusan. From the Collection of the East India 



Company. — Type of Dr. Cantor's P. modestus. 

 e, f. Half-grown and young. China. 

 g. Half-grown. From the Haslar Collection. 



Var. e. P. papilio. 



Syn. — Periophthalmus papilio, Bl. Schn. p. 63. tab. 14; Cuv. ^- Val. 

 xii. p. 190. pi. 353 (caudal fin bad). 



Dark brown, sometimes with a few lighter spots on the sides of the 

 head ; all the fins violet-black : the first dorsal with the margin 

 deep black, and with a lighter band parallel to the margin ; the 

 second dorsal with a longitudinal band, darker than the ground- 

 colour and white-edged. 



Coasts of Ceylon. West coast of Africa. 



a, b. Adult. Ceylon. Purchased of Mr. Stevens. 



c-g. Adult and half-grown. Fernando Po. From Mr. Fraser's 



Collection. 

 h. Adult. Sierra Leone. From the Collection of the Zoological Society. 

 ?'. Half-grown. Africa. Presented by W. Raddon, Esq. 

 Jc. Adult : skeleton. Fernando Po. From Mr. Fraser's Collection. 



The size of the teeth varies considerably in this species, not only 

 according to age, but in specimens of the same size and from the 

 same locality, and even on both sides of the same individual. 



Skeleton. — The skuU has a very singular appearance from the form 

 of the orbital portion of the frontal bones, which are compressed into 

 a thin, narrow, arched lamella, and elevated above the level of the 

 crown. The crown is slightly convex, with a low longitudinal crest 

 along the middle, and with a sharp prominent orbital edge. The 

 maxiUary bone is styliform and nearly straight : the intermaxillary 

 stout, not extending so far backwards as the maxillary ; its posterior 

 process is very long, rather longer than its dental portion. The 

 mandible is of moderate length ; its articular bone is nearly entirely 

 covered by the dentary, which emits a long process posteriorly, di- 

 rected upwards and united to the maxillary by membranaceous liga- 

 ments. The vomer is hammer-like, with the free edges shai'p. 

 There is an oblong and thin praeorbital, and a smaller and stouter 

 postorbital. The bones forming the bottom of the tympanic cavity 

 are only partly ossified, large portions between them being closed by 

 membranes. The tympanic bone is composed of two narrow lamellae, 

 the lower of which extends backwards to the angle of the praeoper- 

 culimi, which has no horizontal portion, but terminates at the angle 

 in a short hook-like process. Beneath the lower portion of the 

 tympanic, there is a narrow flexible bone, which must be considered 

 as an interoperculum. The suboperculum is nearly as large as the 

 operculum, exceedingly thin, its marginal portion being fringed ; the 

 branchiostegal next to it is similarly dilated and fringed. The base 

 of the brain-capsule is broad and slightly convex. 



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