DEVELOPMENT OF THE SKULL IN THE BATRACHIA. 155 



Fifth genus. Rappia. 

 41. Rappna ? sp. — Adult female ; f inch long. Lagos. 



This specimen was collected, with others, several years ago at Porto Novo, near 

 Lagos, by R. B. Walker, Esq., and was sent to me by Mr. T. J. Moore, of Liverpool, 

 on March 24, 1874. 



Dr. GuNTHER was doubtful of the species, although there is a Rappia lagocmis 

 (see GtJNTHER, P. Z. S., June 25, 1868, pp. 478-490 ; a figure of that species is given 

 in plate 40, fig. 2, and a description at p. 487). 



Dr. GuNTHER gives the length of P. lac/oensis as 28 millims. ; my specimen measured 

 only 21 millims., although a female. In the paper just referred to, 15 species of this 

 genus are given — all African. In the "Batrachia Salientia," p. 85, these are described 

 under the generic term Hyperolius, a name now used instead of Uperoleia (ibid., p. 39) 

 for a genus related to Ahjtes. The only Australian kind described in that work is 

 //. hicolor (p. 89) from Port Essington. The author remarks of this, whose skull I 

 shiill describe next, that—" This species is very probably the type of a separate genus." 

 This suggestion is a true one ; the Australian type has an exceedingly different skull 

 from that which I shall now describe from West Africa. 



This skull (Plate 28, figs. 6, 7) greatly resembles the last but one (figs. 1, 2) ; and tlie 

 thought that occurs is this — Are the African Rappice dwarfed "races" of various 

 species of the " Polypedatidi3e;" types which attain so large a size in the Oriental region ? 



This is a rather long skull ; the length and width are equal, and it tends towards 

 the triangular form. The condyles of the quadrate {q.c.) do not reach so far back as 

 in the last but one, they end in front o? the fenestrce ovales. 



The occipital condyles {oc.c.) are similar — they are large and posterior; but tlie 

 basal emargination is less in this species. In conformity with the greater breadth 

 across the ears, the simply oval form of the capsules is lost, and there is a considerable 

 tegmen tympani (fig. 6). The general form of the mid and fore skull is very 

 much alike in both kinds, but they are both a little broader (relatively as well as 

 really) in this small adult ; and the nasal roofs are like those of a metamor])hosing 

 Rana temporaria (see Phil Trans., 1871, Plate 8, fig. 1). The four bony tracts of 

 the hind skull {pr.o., e.o.) are like those of the same of Young Frogs; whilst the 

 girdle-bone is like that of quite old individuals, and the skull, altogether, is a curious 

 mixtm-e of old and young characters. 



The notochord (figs. 6, 7, vc.) is persistent ; there is, as in the last but one, only one 

 lai'ge fontanelle, the tegmen cranii being very short in front, short behind, and not 

 present along the sides in most of the orbital region. 



Below (fig. 7), the prootics and ex-occipitals slightly overlap the wings of the 

 parasphenoid ( j)o..s-.) ; but the cruciform synchondrosis is very large. Below, the 

 ex-occipitals reach half way between the vagus-passage (X.) and the stapes (st.) ; 



X 2 



