66 >AIr. W. NicoU on the 



5-| the distance between tlie origins of the dorsal fins and as 

 long as the longest rays of the second dorsal. Pectoral f^ the 

 length of head, extending to or a little beyond the vertical 

 from the origin of spinous dorsal. 



JIab. Guatemala, Rio Gaacalatc {Salvin). 



Total length 210 mm. 



7. Agonostomus Salvini. 



D. IV, I 8. A. II 10. Sc. 38-40. Closely allied to 

 A. nasutus, but upper lip not so thick, eye smaller, lower jaw 

 a little longer, pectoral fin shorter. Maxillary extending to 

 below anterior ^ or ^ of eye. Dorsal spines moderate, the 

 first § (adult) or ^ (young) the length of head or of the 

 distance between the origins of the dorsals. Pectoral | the 

 length of head or less, not extending to below the spinous 

 dorsal. 



Bab. Guatemala, Rio Nacasil {Salvin). 



Total length 270 mm. 



VII. — A Contribution toivards a Knowledge of the Entozoa of 

 British Marine Fishes. — Part I. By William Nicoll, 

 M.A., B.Sc, Gatty Marine Laboratory, St. Andrews. 

 [Plates I.-IV.] 



The following account of an as yet little-known province of 

 British marine zoology can hardly be regarded as more than 

 a mere preliminary. The original intention was to have 

 treated the subject in a systematic manner, dealing with the 

 Entozoa of each of the natural groups of fishes — Gadidoe, 

 Pleurouectidrfi, &c. — separately ; but as tliis was found im- 

 possible for the time being, the most satisfactory remaining 

 course seemed to be to study the easily accessible fishes as 

 they came to hand. It will be seen that these fall under 

 two classes : (1) the commoner littoral fishes, gunnel, stickle- 

 back, &c. ; (2) the commoner food-fishes, haddock, dab, &c. 

 A large number of each species, except in a few instances, 

 having been examined, the results obtained may be regarded 

 as fairly accurate and the parasites from each host as com- 

 paratively typical. Special attention has been devoted to 

 the Trematode forms ; cestodes occurred but rarely, except 

 in the form of scolices. Nematodes and Acauthocephala 

 were frequent, but, for the most part, assignable to common 

 species. Several forms remain unnamed, mostly young 

 Ascarids, which are difficult to diagnose. 



