586 MR. W. BATESON ON ABNORMAL [JUDC 17, 



right or adradial facet of the axillary 32nd brachial has no pinnule 

 till its third joint, which is not a syzygy, though the fourth is ; but 

 in other respects the arm is normal. The second facet of the axil- 

 lary 30th brachial bears a normal arm of about 60 joints, with a 

 pinnule on the second and a syzygy on the third. Thus, then, the 

 axillary 29th brachial of the primary arm 6^ gives rise to four well- 

 developed arms, two of which bear bifid or trifid armlets, in addition 

 to the larger bifid armlet on the 28th brachial. 



" The primary arm e^ does not seem to have undergone any 

 regeneration and is normal to the 40th brachial. The 41st is a 

 syzygy and the appendage of its epizygal is a short armlet of three 

 joints, the second and third of which bear pinnules laterally, while 

 its main axis is also continued on in the form of a pinnule. The 

 42nd brachial has a similar armlet, with but one lateral pinnule. 

 The 43rd is axillary without a syzygy, its adradial branch being a 

 normal arm with some 40 joints remaining, the second and fourth 

 of which have pinnules, though the third has not. The 44th joint 

 of the primary arm seems to be a syzygy ; and its epizygal, though 

 not regularly axillary, supports an arm which has the first pinnule, 

 as usual, on the second joint, but on the inner instead of on the 

 outer side. The next five joints are all enlarged and bear bifid or 

 trifid armlets, while the remainder of the arm is normal, with 

 regularly alternating pinnules." 



Variations in the number of parts and even in the primary sym- 

 metries are well known among Echinoderms, but Dr. Carpenter 

 informs me that this specimen is quite unlike anything of the kind 

 which he has previously met with. 



V. — Pilchards (Clupea pilchardus) unth the Number of Scales 

 abnormally iticreased. 



In the ' Proceedings ' of this Society for 1887 (p. 129) the late 

 Mr. F. Day described a specimen which he believed to be a hybrid 

 between the Herring (C. harengus) and the Pilchard. The specimen 

 was sent by Mr. Dunn, of Mevagissey. Its peculiarity lay in the 

 fact that the scales on the left side were very many more in number 

 than those on the right side. The number of scales along the lateral 

 line is given as 32 on the right side and 51 on the left. Mr. Day 

 adds that the ridges on the operculum, which are characteristic of 

 the Pilchard as compared with the Herring, were better marked on 

 the right side than they were on the left, though they are stated to 

 have been very distinct on the left side also. 



In the specimen described the gill-rakers were 61 in the " lower 

 branch of the outer branchial arch " ( viz. the bar consisting of the 

 first hypobranchial and ceratobranchial), and it is mentioned that 

 this number is inteimediate between that found in a Pilchard (71) 

 and in a Herring (48) ; but whether this intermediate number was 

 found on the side showing the " hybrid " characters, or on the other, 

 or on both, is not stated. These gill-rakers are also said to have 

 been intermediate in length between those of a Pilchard and those 



