igii.] F. H. Stewart : Cyprinidae from Tibet. 85 



Anus to tail . . . . . , 4*5 mm. 5 mm. 



Pectoral fin, length . . . . . . i'5 ,, 



Maximum height .. .. 2 ,, 



The caudal fin is in process of being formed on the upturned 

 end of the cord. The pectoral fins arise close behind the gill- 

 opening ; ventral not present. The dorsal and anal fins are con- 

 tinuous round the tail. There is a preanal fin. 



They are marked with pigment of two kinds — chocolate-brown 

 and black. The former appears to be situated ver^^ superficially 

 in the skin ; the latter lies more deeply in mesodermal structures 

 such as the peritoneum and periosteum. The skin is so delicate 

 as to be transparent. 



The brown pigment occurs in round corpuscles on the back of 

 the head and body, and in stellate corpuscles on the flanks, on 

 the caudal fin and on either side of the ventral-median fins. The 

 black pigment, on the other hand, is found along the lateral 

 line, on the abdomen and in a few corpuscles on the head. 



In view of what is known regarding the development of other 

 carp, such as Cypriniis carpio, Lenciscus niiilus and idus, and 

 Alburnus lucidus (Ehrenbaum, 3), we will be safe in regarding 

 these young forms as being from 10 — 20 days old, so that, allow- 

 ing 4 — 5 days for hatching, the eggs must have been laid in the 

 second half of June. 



Coming to the older fry, the following table gives the mea- 

 surements in millimetres of the specimens taken during dift'erent 

 months of the 3'ear : — 



March . . 30, 32, 42, 43, 45, 47-— Gyantse, in the Nyang- 



chu, under ice. 



(22,26, 27, 31, 34, 37, 42, 49.— Gyantse, in 

 April . . ] marsh pools. 



( 125. — Ling-ma-tang. 



( 14, 15, 27, 31, 34, 45, 53, 60, 135.— Gyantse. 

 July . . \ 58, 103, 120. — Dochen. 



(. 135. — Ling-ma-tang. 

 August . . 70. — Phari. 

 November . . 32, 35, 36, 40, 42. — Gyantse. 



The November group, clearly, are in their first year, the 

 March and April groups from Gyantse in their second ; there is, 

 however, practically no difference in the measurements if we leave 

 out of account the 125 mm. specimen from Ling-ma-tang. It is 

 therefore probable that an average of 40 mm. represents the first 

 summer's growth, that growth does not occur in the winter months 

 or until May or June and that the 125 mm. specimen was in its 

 third year. The reproductive organs of specimens of about this 

 size are still immature. 



Arranging the specimens in the order of their age we would 

 probably get the following result : — 



