96 



P.H. GREENWOOD 



Fig. 2 Mendosoma lineatum Medial aspect of left lower jaw, cheek region, and hyoid arch. Scale = 2mm. 2a: Maxillary tendon of adductor 

 mandibulae muscle A^ 2b: extension of tendon 2a, joining tendinous aponeurosis of adductor mandibulae muscle Aw; 2c: tendon of 

 adductor mandibulae muscle A 2 ; 3a & b: extensions of adductor mandibulae muscle Aw's tendinous aponeurosis; 6: 

 interopercular-mandibular ligament; 7: interhyal-metapterygoid ligament. 



along, the dorsal and dorsolateral margins of the interopercu- 

 lum, ending at a point about midway between the bone's 

 anterior tip and the face of the prominent, forward-facing 

 articulatory facet for the epihyal (cf pp. 94). Here it attaches 

 to a slight eminence on the dorsal margin of the interopercu- 

 lum. At first sight the ligament appears to be continuous with 

 the epihyal-interopercular ligament (Fig. 3; lig. 4) which also 

 inserts at that point. Careful dissection reveals, however, that 

 the two are separate entities (see also p. 93 and p. 94 

 respectively for the situation in cirrhitids and the latrid 

 Mendosoma). 



Apart from the more complex condition in cheilodactylids, 

 this double linkage of the mandible with the interoperculum, 

 one involving both tendons and ligaments, seemingly has not 

 been recorded in any other teleosts. However, it also occurs 

 in Mendosoma (see p. 94 and Fig. 2) where the lowermost 

 arm of the Aw aponeurosis is attached to the anteromedial 

 aspect of the interoperculum, and in Cheilodactylus (see 

 below, and tendon 5 in Fig. 4). 



As in Mendosoma, the anguloarticular-dentary ligament in 

 A. monodactylus is short and stout. 



An elongate and broad ligament (lig. 7 in Fig. 3) connects 

 the upper face of the interhyal with the quadrate and, mainly, 

 with the entopterygoid. This connection is similar to that in 

 Cheilodactylus (see Fig. 4, and p. 98), and, from its intercon- 

 nections would appear to be homologous with the ligament 

 joining the interhyal with the metapterygoid in Mendosoma 

 (Fig. 2; lig. 7) and the cirrhitid species examined. 



The interhyal-interopercular ligament, present in all mem- 

 bers of the Cirrhitidae examined, is absent in the latrids and 

 cheilodactylids dissected. An interhyal-preopercular liga- 

 ment, present in the other cirrhitoids studied except the 

 cirrhitids, is also developed in Acantholatris . Here, although 



very short, it is stout and has an extensive attachment area on 

 the interhyal and on the preoperculum, which it joins at the 

 point where the upper, vertical arm of that bone begins to 

 curve forward to form its horizontal arm. 



A feature unique to Acantholatris monodactylus amongst 

 the cirrhitoid taxa examined is the presence of a well-defined 

 ligament connecting the hyoid arch and the dentary, a linkage 

 in no way associated with the adductor mandibulae Aw 

 muscle or its aponeurotic system (see Fig. 3). Posteriorly, this 

 ligament is attached to the summit of a distinct prominence 

 on the anterior face of the ceratohyal and situated immedi- 

 ately below the ceratohyal-epihyal suture. Anteriorly, the 

 ligament inserts on the dentary conjointly with the anterior 

 end of the anguloarticular-dentary ligament (see above and 

 Fig. 3; lig.l). 



The family Cheilodactylidae 



The account which follows is based on dissections of Cheilo- 

 dactylus fasciatus Lacepede. Since the situation is virtually 

 identical in two other cheilodactylid species studied, Cheilo- 

 dactylus pixi (Smith) and Chirodactylus brachydactylus 

 (Cuvier), the term Cheilodactylus is used to cover all three 

 taxa. What interspecific differences do exist are noted on 

 page 98. 



Of all the cirrhitoid species examined, the ligament and 

 tendon systems separately or conjointly linking the mandible, 

 the hyoid arch, the opercular series, and the palatoquadrate 

 arch in Cheilodactylus are by far the most complex. The 

 greatest similarities, however, are with those systems in the 

 latrid Acantholatris monodactylus (cf. Figs 3 & 4). In the 

 cheilodactylids examined, and like A. monodactylus, there is 

 no obvious subdivision of the adductor mandibulae Aj 



