Notes, iv. 12 — 13. • 247 



33. Although A. speaks here of the wryneck ( Yunx torquilld) as the only bird that 

 turns two toes backwards, elsewhere {,H. A. ii. 12, 4) he says there are several in which 

 this is the case. Probably he there refers to cuckoos or woodpeckers or owls, which 

 latter, as also the osprey, can turn the outer toe backwards at will ; for he had apparently 

 never himself seen a parrot. (Cf. ii. 17, Note 3.) 



34. D. G. i. 12. 



(Ch. 13.) 1. The main characters assigned by A. to Fishes were as follows. They 

 are sanguineous ovipara, with sexes almost, though not quite, invariably distinct (Z>. G. ii. 

 5, 7); producing either a perfect ovum (selackia), which is hatched internally, the embryo 

 in such case becoming exceptionally {mustclus) attached to its mother's uterus (D. G. iii. 

 3, 10), or an imperfect ovum, one that is that grows after deposition (D. G. iii. 5, 6 ; 

 Introd. p. xxvii). In either case the ovum differs from that of Birds and Reptiles in 

 presenting no distinction of white and yelk (Z>. G, iii. 3, 8-1 1), and in giving rise to an 

 embryo with only one umbilical appendage (Z>. G. iii. 3, 4 ; /T. A. vi. 10, 3). The 

 skeleton is formed not of true bone, but of a spinous substance or of cartilage, and small 

 spinous bones are to be found isolated in the flesh \H. A. iii. 7, ll). There are usually, 

 though not always, scales externally, never hairs nor feathers. The place of limbs is 

 supplied by fins, of which the ventral pair are often missing, and occasionally both pairs 

 (Notes 10, 1 1). There are gills in place of lung ; no bladder nor kidneys. The seminal 

 organs are hollow tubes, and there are no solid ovoid bodies like the testes of Viviparous 

 Quadrupeds and Birds (cf. Note 34). The generative outlet is one with the foecal (cf. 

 Note 36), with apparently some exceptions (cf. iv. 10, Note 32). The teeth are sharp, 

 but not adapted for mastication ; the oesophagus is absent or short ; processes, often 

 numerous, are usually given off from the intestine close to the stomach (iii. 14, 14 ; H. A. 

 ii. 17, 26) ; there is always a gall-bladder (iv. 2, i). 



They are divided into two great groups: (l). Those with a cartilaginous skeleton; 

 which with one exception (cf. Note 5) are ovoviparous. This group is subdivided into 

 the Elongated species, i.e. sharks and dog-fishes, and the Flattened species, i.e. rays 

 and skates, with which A. classes the oviparous fishing-frog (cf. Note 5). (2). Those with 

 a spinous skeleton, and oviparous. 



The former group he calls Selachia ; to the latter he gives no special name. 



2. I cannot say to what passage A. refers. But his explanation of the substitution of 

 fins for limbs is given a little farther on in this chapter. 



3. The electric rays or Torpedos are found abundantly in the Mediterranean, and must 

 have been well known to A., who frequently speaks of them. Yet in these the tail is 

 far from being spinous and elongated, as compared, that is, with other rays. Frantzius 

 suggests therefore that some error has got into the text, and that perhaps Batos should 

 be read instead of Torpedo. A similar correction would have to be made a few lines 

 farther on, 



4. The Trygon is doubtless the Trygon Pastinaca or sting-ray, which is abundant in 

 the Mediterranean. 



5. The Batrachus or fishing-frog is the Lophius piscatorius, often mentioned by A., 

 and erroneously classed by him with Selachia. Into this error he was doubtless led by 

 the somewhat ray-like form of this fish, by the semi-cartilaginous character of its skeleton 

 {Cuvier, R. An. ii. 250), and by its naked skin, rough with warts and tubercles. A. did 

 not fail to observe that the Batrachus differed in many important points from the rest of 

 the group; in being, for instance, oviparous ^De Gen. iii. 3, i); and in having an 

 operculum for its gills, and the gills themselves placed laterally (//. A. ii, 13, 7). A. 

 had clearly examined the fish with some care ; for he notices (cf. iv. 2, Note l) the 



