no MR. \V. K. PARKER ON THE STRUCTURE AND 



lire tboroiiglily anchylosed to each other, and to tlie subjacent bone. The pre- 

 maxillaries and maxillaries {px., mx.) are strong, smooth, high, and typical ; and 

 there is a large septo-raaxillary (s.mx.) on each side. The falciform quadrato-jugal 

 (figs. 1, 2, 3, and 5, q.j.) is perfectly continuous with the bony quadrate (q.) ; the 

 squamosals (sq.) are like a hammer with a wide handle and a very short head ; this 

 latter part lies on the tegmcn tympani but little (fig. 1, sq.). 



The nasals (figs. 1 and 3, n.) scarcely hide the fore jJart of the girdle-bone, and 

 leave the pouched short nasal roofs naked ; they are narrow, convex, curved shells of 

 bone, with a descending narrow process, outside. 



The vomers {v.) are small and have a post-narial spur, but none in front of the 

 passage ; the fore part is narrow and bifid ; the dentigerous lobe is oval and less than 

 normal. Tlie parasphenoid (fig. 2, jya.s.) is large, normal, rather blunt and ragged in 

 its processes, and is somewhat confluent with the superjacent bone, behind. 



Next to the skull of Bomhinator and Pelohates this Frog shows most what is low 

 and generalised in its skull, it differs from the " norma" in : 



1. The large relative size of the auditory capsules. 



2. The shortness of the nasal capsules. 



3. The unfinished roof 



4. The intense and almost universal ossification of the endocranium, and the 

 anchylosis of the outer roof and floor bones. 



5. The differentiation of an endoskeletal metapterygoid on the o^iqlit side. 



(5. The smallness of the upper part of the squamosal and of the applied "annulus." 



7. The arrested state of the columella. 



8. The almost entire closing of the first cleft. 



9. The short, wide form of the basal plate, and its semi-osseous condition. 

 10. The narrowness of the internasal region, and small size of the vomers. 



26. Cyclorhamphus culeus*. — Larva ; length, Z\ inches : tail, 2 inches ; hind legs, 

 7 lines. Puno, Lake Titicaca, Peru. 



I am very fortunate in being able to give the structure of the larval skull in a 

 qeographical neighhour of the great Calyptoceqihalus ; this is one among many of the 

 things I owe to my friends Agassiz and Garman. 



Moreover, among the various kinds of larval skulls worked out by me, this comes 

 Jie nearest to that of that helmeted Frog ; and as we know in the case of Bomhinator 

 and Pelohates how weak one skull, and how strong another, may be, in congeneric 

 types, there is no diflicidty on that head as to the relationship of these two 

 Neotropical forms. Cyclorhamphus marmoratus (DuM. and Bib.) evidently comes 

 between these two forms in respect of its adult skull (Agassiz and Garman, p. 277). 



• For an excellent figure of the adult of tliis fine species, see Agassiz and Garman, " Bulletin of the 

 Museum," No. 11, plate 1 (Cambridge, Mass., November 26, 1875). 



