OBSERVATIONS, 



19 



mda glauca, feeding upon the larva of 

 Dytiscus marginalis ; lie also read the fol- 

 lowing description of the Geometrical Leech 

 Piscicola piscium, (Hirudo geometrica, h.J 

 "Body elongate, terete, gradually attenuated 

 anteriorly, with suctorial discs at each 

 extremity, the posterior larger than the 

 anterior ; colour variable, usually greyish, 

 closely sprinkled with irregularly shaped 

 brown dots, the interruption of which at 

 regular intervals marks the body out into 

 segments ; the disposition of these dots in 

 the posterior disc is radiate, in the anterior 

 somewhat cruciform ; a row of whitish dots 

 extends down each side. Length, about one 

 inch ; progression, geometrical, swims, like 

 a leech, by undulations of its body ; habi- 

 tat, affixes itself to stones in clear streams. 

 The habits of this animal in confinement 

 are very interesting. If two freshly cap- 

 tured specimens be placed in the same 

 vessel of water they frequently seize each 

 other by twisting the foreparts of their 

 bodies together, so as to resemble a knotted 

 cord. Two leeches thus entwined will 

 maintain their hold upon each other for 

 half an hour or an hour, and when they 

 separate each of them has a v/hitish fungus- 

 like excresence protruding from its side. 

 This embrace often results in the seeming 

 death of one of them, for after the contact 

 one of them is generally found lying at the 

 bottom of the vessel, twisted into a pain- 

 fully tight spiral. May not this be an act 

 of reproduction ? Another remarkable 

 habit of this creature is the avidity with 

 which it seizes fish that come into its way ; 

 a stickleback on being put into a jar of 

 water containing three of these leeches 

 was almost instantly seized by them in 

 succession, and all the elforts of the fish 

 to dislodge them were inefi'ectual, their 

 hold upon anything to which they attach 

 themselves being most tenacious. It is in 

 the habit of fixing itself to stones in clear 

 swift streams, probably there lying in wait 

 for the chance of seizing the fish, such as 

 trout, sticklebacks, lampreys, &c., which, 

 in ascending the streams, take advantage 



of the eddies to rest, and thus bring them- 

 selves within the range of this parasite. " — 

 John Peers, Hon. Sec. 



Ax^pearance of the Cuckoo. — This summer 

 visitant was first heard here on the 9th of 

 April. — John Eanson, Linton- on Ouse, 

 York. 



Sioallows. — Half a dozen Bank Martins 

 ( Hirundo riparia ) were seen hawking on 

 the Ouse, on April 9th, and my two chim- 

 ney swallows ( Hirundo rustica ) were first 

 seen on the 16th, and other two, which 

 build in a neighbour's cowhouse were seen 

 the same day. About six o'clock on the 

 19th, I was witness to the arrival of a 

 flock of about fifty. They seemed very 

 much fatigued, and rested for a considerable 

 time on the ridge of a cottage, after which 

 they dispersed to difi'erent parts of the 

 village. — John Eanson. 



Arrival of Summer Migrants. — It is 

 with great pleasure, after a long and severe 

 indisposition, I am enabled to send you 

 notice of the first appearance this year of 

 the following summer migrants : Wryneck, 

 April 13th ; Swallow, April 16th ; Night- 

 ingale, April 18th ; Cuckoo, April 18th ; 

 Redstart, April 16th ; Lesser Whitethroat, 

 April 23rd ; Greater "Whitethroat, April 

 23rd ; ChiffchafF, April 23rd ; Willow 

 Wren, April 23rd. I have kept a 

 close watch upon the beach, but as yet I 

 have not noticed the appearance of any 

 of the spring birds of passage which always 

 resort to this shore for a few weeks prior to 

 their departure for their breeding gTounds 

 in the North ; they appear very late this 

 season as do also the smaller insessorial 

 birds of passage. — Samuel P. Saville, 

 King's Lynn, Norfolk. Hunstanton Hall, 

 April 23rd, 1865, per the Eev. F. 0. Mor- 

 ris. 



Scarcity of Swalloivs. — Ten days or a 

 fortnight ago I noticed in the "Times" a 

 note from one of their correspondents on 

 the arrival, or non-arrival, up to that date^ 



