188 PEOF. W. K. PAEKEE ON THE MOEPHOLOGT 



The parasplienoid (pa.s) is essentially like that of Cynops. The postorbital part of the 

 large squamosal is almost as large as the part which lies over the two anterior ampulla} ; 

 the fore part curves inwards to join the postorhital process of the frontal. A carinate 

 preopercular process runs down outside the suspensorium, binding the quadrate (PL XIX. 

 fig. 5, sq, q). 



The mandible (figs. 6 & 7) is feebler, lower in the corouoid region, and has a smaller 

 splcnial bone (sp) ; the condyle is a large oval tract of cartilage. Each ramus, as 

 usual, is tied to its fellow at the chin by a strong interosseous ligament. 



The hyobranchial apparatus (PI. XIX. fig. 8) might have belonged to a half-grown 

 Cynops ; the bony centres are shorter, only half as much developed, and there is no 

 bone in either the first basibranchial (b.br 1 ) or on the second cerato-branchial (c.br). 

 Another arrested state is shown in this, that the Avhole end of the second basibranchial 

 (b.br") remains as a transverse thyrohyal, and is not broken up into two segments, as in 

 the last two kinds. 



Thus this species, conforming on the whole very accurately to the highest Caduci- 

 branchiate type, is, nevertheless, somewhat arrested in development as compared with 

 some other kinds. 



Species 5. — The Skull of Onychodactylus (? species). Japan. Total length of animal 



2£ inches. 



The study of tins type wrought much surprise in me : to all appearance it seems to be 

 a genuine Caducibranch, yet in development it has not advanced much further than in the 

 ripe young of Salamandra maculosa (PI. XV.); and its position in the " Order" would 

 appear to be among the Cryptobranchs, or those whose branchiae arc almost absorbed. 

 When I come to describe the skulls of the Menopome and Siren, it will be seen that in 

 many respects they are quite as much metamorphosed in their skull as this species. 



The sharp toe-ends of this kind suggest the presence of nails ; but I could find no 

 special development of the epidermis on the upper surface; yet I carefully examined 

 the toes at Prof. Mivart's request, to whom I owe this and many more Amphibian 

 treasures. 



The cranial territories are very equally composed of cartilage and bone ; and the 

 secondary bony plates correspond to those of the larvae of Caducibranchiate skulls — larvae 

 that have their gills full-sized or in full play. 



The existence of so small an Amphibian as this lingering on the headland of the lowest 

 tribes is very interesting, more especially as it coexists in Japan, if not with the lowest, 

 yet with the largest of these waifs of a subextinct group. I refer to Sieboldia. In 

 South Europe we have the loioest, namely Proteus anrjuinus ; but this creature is an 

 "albino " prisoner in the waters under the earth. Yet, with the exception of this kind 

 and of the Gigantic Salamander of Japan, I am not acquainted with any other species 

 of the lowest group outside North America. 



There, still flourish the Menobranchus (which is next above the Proteus), the Meno- \ 

 pome, the Siren, and the Amphiuma ; the small true Caducibranchs (they are all of 

 small size) have a wide geographical distribution. 



