64 Pari III. — Twenty-eighth Annual Report 



Abnormal Ovartj of an Haddock {Gadus ceglefinus). 



A peculiar roe of an haddock was received from Mr. Erlandsson on 

 February 12, 1910 (fig. 51a). It was hard, tough, and of a red colour. 

 It was the left ovary ; it measured 2^ inches in length. The outer surface 

 was finely tuberculated or bossed. 



It was evidently an ovary that had been ripe, but which had not been 

 spent. Internally, the ovary was dry towards the rind. About the centre 

 it was suffused with red. The eggs were semi-translucent and hardened. 

 They were apparently still in follicle. The ovarian tissue was suffused with 

 blood. There seemed to have been hsemorrhage inside the ovary. 



Abnormal Skate {Rata circularis and Raia clavata). (Figs. 37, 49, 49a.) 



An abnormality which, while not common, is not very rare, is the 

 partial separation of the pectoral fin from the snout. 



Three instances have come under my notice. A well marked case occurred 

 in a male Cuckoo skate [Raia circularis) which was landed at Aberdeen in 

 September 1909 (fig. 37). The separation extended backwards to the 

 level of the edge of the orbit. The tips of the pectoral fins bore large 

 hooked spines, similar in size to those that bordered the orbit. This is a 

 character of the male fish; the female shows only small spines on the 

 anterior corner of the fin. 



If the lateral peaks be pressed in to touch the snout, a practically normal 

 condition is attained. 



It might be suggested that this abnormality may have been caused by a 

 fisherman who had cut into the fore end of the skate and then set it free. 

 The separation is, however, carried exactly along the dividing line between 

 the snout and the fin, on either side. No part of the fin-rays or muscles 

 was left attached to the snout. It would, therefore, appear probable that 

 this condition has occurred naturally. 



Two cases were observed in Raia clavata, and both of the fishes were 

 female. One of these (fig. 49a.) measuring 18| inches across, closely 

 resembles the circidaris. The other (fig. 49) was somewhat different. 

 This skate measured 18 inches across the body. The anterior ends of the 

 pectoral fins are notched, but in a manner dififerent from the cases just cited. 

 The clefts are smaller and offer a wider angle. Here, moreover, the most 

 anterior fin-rays and their muscles remain attached to the snout on either 

 side. The angle between the fin-rays, that are directed anteriorly and those 

 turned laterally, is filled with muscles in which the bundles run in two 

 directions at least (fig. 50). 



In this case also, if the abnormality has been artificially caused, the fish 

 has been very accurately cut to form a symmetrical figure. 



There were six pairs of external gill-openings. The sixth pair was not, 

 however, functional. The slit was imperforate, being simply a depression in 

 he skin. 



Day exhibits a similar monstrosity in this species, and Johnstone* 

 describes a small clavata which had clefts which entered the body nearly as 

 far as the first gill-openings. The last fish was apparently in good health 

 when it was captured. An example recorded by Traquairf was not so 

 deeply cut as the preceding specimens. 



* "Ray showing Arrested Development of the Pectoral Fins." No. xiv. Report 

 for ] 905 011 the Lancashire Sea-Fisheries Laboratory and Sea-Fish Hatchery, Liverpool, 

 1906, p. 188. 



t " Note on an abnormally developed Thornback {Raia clavata, L.)" Annals oj 

 Scottish Natural History for 1892, p. 29, fig. — . 



