198 



SUB-CLASS (AND ORDER) TELEOSTEI. 



developed behind the old one, comes to lie beneath it, so that 

 the succession is vertical. 



The teeth are generally conical, and may be minute, slender and sharp- 

 pointed (villiform, e.g. Perch), or longer but very fine (ciliiform, setiform, 

 as in Chaetodonts). Larger conical teeth are termed card-like (rasp-teeth, 

 raduliform). In Goniodonts the teeth are bent on themselves like a 

 tenterhook. They may vary in shape in different parts of the mouth, 

 the anterior teeth being conical, and the posterior broad and molar-hke 

 for grinding the food, as in the wolf -fish (Fig. 117), and many Sparidae. 

 In Sargus indeed the anterior teeth are incisor-Uke, and in Dentex there 

 are canine-like teeth. Small molar -like teeth are called granular. 



Ill Labrus crushing teeth are borne by the upper and lower pharyngeal 

 bones. Compound teeth, which are found in the Gymnodonts and the 

 Scari* are made up of a number of teeth which are developed successively 

 but are joined by cement when full grown and functional. They thus 

 present the appearance of teeth which continue to grow throughout life. 

 Pharyngeal teeth may be present on the superior and inferior pharyn- 

 geal bones. In the Cyprinoids the mouth is edentulous, and teeth are 

 only found on the inferior pharyngeal bones, which bite against a tubercle 



on the basi-occipital. They 

 are also present on the edges 

 of the branchial arches, but 

 except in a few cases, e.g. 

 Orthagoriscus, in which they 

 are long and sharp, these gill- 

 teeth are little more than 

 horny excrescences, which 

 however are sometimes elon- 

 gated into setiform horny 

 processes — the gill-rakers. 



Fia. 117.— Teeth of the Wolf fish, Anarrhichas lupus 



(after Ounther). _, . „ , 



There is usually on the 

 floor of the mouth a small non-muscular elevation which 

 represents the tongue ; it is supported by the glosso-hyal, 

 and is sometimes toothed. The oesophagus is a wide 

 tube, hardly if at all marked off from the stomach. The 

 stomach, which varies in form, is usually but slightly dilated 

 and is either U-shaped as in Elasmdbranchs, or is provided with 

 a caecal prolongation of its cardiac portion and a short pyloric 

 region placed near the junction with the oesophagus (Fig. 37). 

 The intestine is usually slightly convoluted, is without a spiral 

 valve (though a trace of one may be made out in some genera), 

 and opens to the exterior by the anus. In some forms (e.g. 

 Tinea, Cobitis) the striped muscles of the oesophagus are con- 

 tinued over the stomach and intestine outside the smooth 



• J. E. Boas, Die Zahne der Scaroiden, Z. /. w. Z., 32, 1879, p. 189-216. 



