110 
MR. W. K. PARKER ON THE STRUCTURE AND 
are thoroughly anchylosecl to each other, and to the subjacent bone. The pre- 
maxillaries and maxillaries (px ., rnx. ) are strong, smooth, high, and typical; and 
there is a large septo-maxillary (s.rnx.) 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 witli a wide handle and a. very short head ; this 
latter part lies on the tegmen tympani but little (fig. 1, sq.). 
The nasals (figs. 1 and 3, n.) scarcely hide the fore part 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. The parasphenoid (fig. 2, pa. si) is large, normal, rather blunt and ragged in 
its processes, and is somewhat confluent with the superjacent bone, behind. 
Next to the skull of Bnmbinator and Pelobates 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 right side. 
6. 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. Cyclorliamphus culeus*. —Larva ; length, 3} 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 
geographical neighbour of the great Calyptocephaius; 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 
the nearest to that of that helmeted Frog; and as we know in the case of Bombinator 
and Pelobates how weak one skull, and how strong another, may be, in congeneric 
types, there is no difficulty on that head as to the relationship of these two 
Neotropical forms. Cyclorliamphus 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 this fine species, see Agassiz and Gasman, “ Bulletin of the 
Museum,” No. 11, plate 1 (Cambridge, Mass., November 26, 1875). 
