Notes from the Gatiy Marine Laboratory . 291 



L. — Notes from the Gatty Marine T^ahoratory, St. An- 

 drews.— "So. XXII. By Prof. M'Intosh, M.D., LL.D., 

 F.R.S., &c. 



1. On Abnormal Coloration in the Pleuronectids. 



2. On the liritish Syllido'. 



3. On tho Si/Ui(he of the ' Porcupine ' Expeditions. 



4. On Norweirian Sylliche collected by Canon Norman, D.C.L., F.R.S. 



5. On the Boring of Pobjdora in Australian Oysters. 



1. On Abnormal Coloration in the Plenronectids. 



About a dozen adolescent turbot liave lately been obtained 

 in the nets for plaice in the Bay sliowing a deep notch above 

 the head, the dorsal fin terminating in a prominent hook. All 

 these were coloured on botii sides. The following may be 

 taken as examples: — 



No. 1 was about 9 inches in antero-posterior diameter and 

 8 inches in transverse diameter. The left eye was normal in 

 position, whilst the right was barely clear of a line drawn 

 from the edge of the dorsal to the tip of the snout. This eye 

 had extensive vision, since in life the dorsal tin, even on the 

 bottom, was below it. Every part of the under surface was 

 as deeply pigmented as the upper. The prickles were, how- 

 ever, considerably less numerous and less prominent than on 

 the left side ; but their occurrence lends support to the view 

 that we have to deal with more than the effect of liglit. 



2. A s])ecimen about tlie same size and having the dorsal 

 fin terminating in tiie hook-like process above the head, a 

 lirje from the distal edge of the latter just touching the front 

 of the eye. The pigment was equally developed on both 

 sides, as in the former case, but the prickles were somewhat 

 more numerous and more prominent than in tiiat form. 



3. A living example in the tank is somewhat larger than 

 the preceding, viz. about 10 inciies, but has precisely the 

 same arrangement of the dorsal tin, which terminates in a 

 hook-like process behind the head. The eyes are in the same 

 position. Jt is evident from an examination of this example 

 that the dorsal and anal fins are used in the tank, and probably 

 in nature, as partial supports, and in the case of the dorsal 

 fin the right eye (which lias passed to the left side) thus has 

 a much wider area of vision tlian is apparent from a study of 

 spirit-specimens. 



4. A male turbot 13^ inches in length and 11 inches in 

 greatest breadth had a deep notch above the head, the tip of 



