52 report — 1865. 



it by Willughby and Yarrell ; but tbe particulars of this difference, as well 

 as the way in which it was caught, it would be tedious to give now, and 

 Mr. Couch reserves them for his work on our native fishes that is now pub- 

 lishing. Also an account of another fish which we have obtained within a 

 few days (Aug. 18th), and now report for the first time as a visitor to our 

 coasts. This is the Short-finned Tunny, Thynnus hraehyterus of Cuvier; an 

 example of which we procured from Mevagissy, and a second from Polperro ; 

 Mr. Couch has made drawings of both these rare fish. 



We also obtained from the trawl a specimen of Myliobates aquilce, or Eagle 

 Ray. 



MOLLTTSCA. 



Among the Mollusca of more or less interest the following are recorded : — 



An exceedingly fine specimen of Octopus vulgaris, as well as of Loligo 

 media, Sepia elegans, and S. officinalis. Also the ova of a Sepia, containing 

 the rudimentary shell, apparently differing from those of S. officinalis, but of 

 what species we have not yet been enabled to determine. 



A beautiful specimen oildalia elegant, far more brightly rose-coloured than 

 the figure given by Messrs. Alder and Hancock, from which our specimen 

 also differed in the posterior extremity of the foot, terminating in three in- 

 stead of a single point. 



We might also mention a specimen of Avicula being taken about half an 

 inch longer than the greatest length ascribed to it by Prof. Edward Forbes. 



Crustacea. 



The first species of crab to which we shall allude is that of Achceus 

 cranchii, spoken of by Bell as being rare ; two specimens only being re- 

 corded, one from Ealmouth, the other from the South of Ireland. 



Certainly this little crab is by no means uncommon off the coast of South 

 Devon, in depth from six to twenty fathoms. This circumstance enables us 

 to state that the second and third pairs of pereiopoda are not drawn of suffi- 

 cient length in proportion to the two posterior, in both Prof. Bell's and Dr. 

 Leach's figures of the species. 



Among the specimens that we dredged, we took two from six fathoms of 

 water near the Knapbury, that possibly may be a second species. Our atten- 

 tion was first drawn to the circumstance from observing a peculiarity in its 

 habits from that of the known species, which is that it covers itself with 

 weed as we know is done by those of the genus Pisa. 



In Pisa this is no accidental occurrence, since all the spines are sharp- 

 pointed and curved ; and my friend Mr. Whitford has informed me that he has 

 observed specimens in his aquarium which soon after having cast their 

 exuviae, pick up with the claws pieces of weed and place them on the spine. 



In Achceus cranchii the spines are straight, a circumstance that gives the 

 animal generally a hairy appearance. In the second form the spines are not 

 visible to unassisted observation, and the legs of the animal look smooth and 

 free from hairs, but a nearer and closer inspection shows that the spines are 

 all hooked as in Pisa. The form of the eye somewhat varies also; but 

 whether these are sufficient to ground a specific distinction of the two ani- 

 mals, we have not quite determined, particularly as we have observed among 

 the mass of straight hairs in A. cranchii a few hooked ones also. 



Of the interesting genus of soldier- crabs, Pagurus, we have taken six or 

 seven species, viz. — 



P. bernhardus. P. hyndmanni. P. laevis. 



prideauxii. dillwynii. ulidianus. 



cuanensie. 



