552 



ANATOMY OF VERTEBRATES. 



368 



Mucous follicles abound in the skin of all the Batrachia : they 

 are found in linear rows in parts of the Siren : ! are more generally 

 diffused in the Axolotl. 2 In the Frog they are spheroidal, 3 fig. 

 368, d, or subdepresscd, 4 situated in the superficies of the derm, c\ 

 their ducts perforate the epiderm, b, and terminate by rounded 5 

 or triradiate 6 orifices, ib. B. Like the lateral canals of Fishes, 

 they usually contain a clear fluid, which they expel on irritation 

 of their nerve, ib. /. 7 This fluid, in the Newts and Toads, 



appears to possess an acid or 

 irritating property. A stork will 

 swallow a frog, but rejects a toad, 

 if picked up by mistake. The 

 cutaneous follicles are more local- 

 ised in the land Salamander, 

 and their secretion is whitish and 

 opake, of an acrid nature, and 

 poured out abundantly when the 

 animal is alarmed or irritated. 

 The cutaneous follicles are nu- 

 merous and close-set in the 

 American Newts of the genera 

 Ambystoma and Plethodon, in 

 which they exude a milky fluid. 8 

 Special aggregates of cutane- 

 ous follicles occur in most 

 Batrachia. In the land Sala- 

 mander they form a porous 

 tubercle behind each eye. In 

 many Anoura the homologous 

 glandular tubercles ( f parotoids ' 

 of Giinther 9 ) are conspicuous 

 above the tympanum (Alytidce, Bufonidci) : they are enormous in 

 Bufo agua, and are situated on each side of the neck in Uperoliidce. 

 In Bufo calamita, besides the ordinary parotoids, there is a similar 

 glandular tubercle on the upper side of the legs. The skin of 

 the back in Kalophrynus is thick and glandular, like a parotoid. 

 In Hylarana the skin has two glandular folds, one on each side of 

 the back, usually of a white colour. Platymantis plicifera has 

 several pairs of such longitudinal folds or ridges. 10 In Polypedates 



1 xx. vol. iii. p. 277, prop. no. 2108. 2 CCLXXIX. tav. ii. fig. 7. 3 ccxcv. taf. 

 ii. fig. 10. 4 Ib. fig. 7. 5 Ib. fig. 2. 6 Ib. fig. 3. 7 Ib. (6841), p. clvi. 



8 ccxcvr. p. 281. Printed by mistake ' paratoid ' in his excellent Catalogue. 



10 CLXXV. p. 96, pi. viii. fig. B. 



Section of tegument and cutaneous glands of 

 the Frog, magnified, coxcv. 



