44 MR. F. DAY ON ACANTHIAS VULGARIS. [Feb. 5, 



EXPLANATION OF PLATES II. & HI. 

 Plate II. 

 Fig. 1. Anomalanthus tumidus : nat. size. 



Plate III. 

 Fig. 1. A. tumidus, profile view (f nat. size). 

 Fig. 2. Apical area, and upper coronal plates ( X 2). 



Fig. 3. Portions of a poriferous zone and adjoining plates, to show the character 

 of the tubercles and miliaries. 



February 5, 1884. 

 Professor Flower, LL.D., F.R.S., President, in the Chair. 



Prof. Flower made some remarks on the principal points of interest 

 exhibited by the Burmese Elephant, deposited in the Society's 

 Gardens by Messrs. Barnum, Bailey, and Hutchinson. 



Mr. F. Day, F.Z.S., exhibited a specimen of a Dog-fish (Acanthias 

 vulgaris), and made the following remarks : — 



" The specimen exhibited is that of a female Dog-fish (Acanthias 

 vulgaris) 27 inches in length, consisting merely of the skin (including 

 even that covering the eyes) and skeleton, out of which I have removed 

 about 20 examples of the elongated Isopod Gonilera cylindracea, 

 some of which measured as much as 1 \ inch in extent. The spiracles, 

 vent, and an orifice behind each pectoral fin appeared as if they had 

 been enlarged or made by these parasites, which had devoured the 

 whole of the soft parts of the fish. The history of these fish-parasites 

 as known at Mevagissey I gave at a meeting of the Society in 1879 ; 

 I will therefore merely observe how this fish was captured. 



" On January 30 I received a box of fish from Mr. Dunn, of Meva- 

 gissey, and he remarked that he had sent, among other things, Dog- 

 fish, or, rather, the skin of one, as the entrails of the creature had 

 been entirely eaten out by the lice. The fish he had personally 

 captured in a mullet-net which he had set half a mile from land on 

 sandy ground to secure Dog-fishes. Of these he had taken 100 at 

 one time ; but nearly every fish was found to have been eaten in a 

 like manner by the lice. 



"Subsequently Mr. Dunn advised me that these lice {Gonilera 

 cylindracea) in the summer months are found from 15 to 20 miles 

 from land, generally on soft and sandy bottoms. When the fishermen 

 in foggy weather get on this bottom, they call it " lousy ground." 

 When the lice are abundant they drive away the Congers and other 

 fish. Often a shoal of Bream will come and eat them up. As these 

 parasites devour fish in a few hours it seems hardly possible with 

 their habits to class them as fixed ; they would seem to pertain to 

 those which are free, as they hunt in large shoals, and must be 

 constantly moving from place to place in search of food." 



