96 MR. W. K. PARKER OX THE STRUCTURE AND 



less, and tlie pterotic processes {pt.o.) are much shorter. The parotic wings are much 

 less, for this skull is only one-thirtieth wider than long. The canals are well marked 

 {a.s.c, h.s.c, p.s.c), also the whole occipito-auditory region is ossified, and this bone 

 runs up to the optic fenestra (IL). Between and a little below these spaces the floor 

 of the skull is cartilaginous ; but from thence up to the middle of the septum nasi, 

 along the axis, the endocranium is all ossified, and the bone runs into the extremely 

 large ethmo-jjalatine (e.pa.), leaving only the pre-palatine hook (jjr.pa.) soft. Above, 

 the bone is continued nearly to the front of the broad transverse snout, so that there 

 are only a few places where cartilage remains. Behind, only the outside of the 

 auditory floor is left below, and the pterotic angle {pt.o.) above, whilst behind these 

 parts only the condyles retain their bark of cartilage. The three fontanelles (fig. 6) 

 are quite normal, but they are rather small, as there is very much ossified overgrowth 

 of cartilage {tegmen cranii). 



The orbital region is almost oblong, rather narrower in front than behind, and 

 bulging very little. The roof (al.n.) of the nasal region is well developed ; the floor is 

 of less extent than in C. ocellatus, but the pro-rhinals {p.rh) are large and hooked. 

 The huge bony ethmo-palatines {e.pa.) help the bones to enclose the large circular 

 nostrils {i.n.), which are wide apart ; the palatine bones {pa.) are well developed, 

 falciform, and with an additional inferior sharp crest. 



The pterygoids are feeble and sinuously inbent, with a much shorter part for the 

 pedicle {pd.) than in the last ; they have consumed nearly all the cartilage. The 

 Eustachian passages {eu.), lying in their angle, is sub-pp-iform in outline. 



The quadrate is well ossified by the quadrato-jugal {q.j.), and the condyles {q.c.) 

 are large well-made trochlefe. The an nidus {a.ty.) is large and perfect ; the stapes 

 (figs. 6, 7, and 10, st.) is oblique, emarglnate, and has a boss ; the feeble columella has 

 a large undivided emarginate unossified proximal j^art ; the bony bar {m.st.) is feeble 

 and curved. The extra-stapedial {e.st.) is a small irregular hook, and its ascending 

 process is fibrous. 



The mandible (fig. 8) is rather slender; it has a long condyle {ar.c), a sharpish 

 coronoid crest (ar.), a short dentary {d.), and a well-formed mento-Meckelian (rn.wA:.). 



The stylo-hyal (fig. 7, st.h.) is confluent above ; the hyo-branchial appai'atus (fig. 9) 

 is similar to the last, very elegant in form, has its front lateral lobe dentate in front, 

 its basi-branchial ossicle {h.hr.) divided in the middle, and there is a band of bony 

 deposit along the edges of the basal plate ; the thyro-hyals {t.hi/.) are long, straight, 

 and slender. 



The nasal valve-cartilages {u.P.u.l'-.) are well developed. 



The investing bones are also well developed; the fronto-parietals {/.p.) cover the 

 temporal and part of the epiotic region, just roofing the lesser fontanelles, behmd, 

 ■where they form a straight margin; also in front they form a straight margin, and only 

 just cover in the large fontanelle (fig. fi). The nasals (n.) are large, but less irregular, 

 convex, and ribbed than in the last. The marginal bones {px.,mjc., q.j.) are all normal ; 



