8o THE BRITISH NATURALIST. [April 



The facts related by Mr. Sanborn concerning the ' milk ' and its 

 absorbtion by the young Lycosas are very interesting, not to say 

 startling. He will probably be aware that the natural excretal fluid, 

 white with solid black particles, issues from the anal orifice situated 

 immediately above the spinnerets. Most of the females with young 

 which have come under my observation, were rather shrivelled up 

 than otherwise. 



As to the food of the young of other spiders I cannot speak with 

 any certainty either, though I can affirm that they are capable of 

 capturing small flies, etc., at a very early age. — F.O.P.C. 



The Ivory Gull at Hartlepool. — A fine specimen of this rare 

 gull was brought me to-day for identification. It was shot by Mr. 

 R. Loughborough on the North Sands on the 21st January, and is now 

 in the possession of Mr. Jas. Pounder. — John E. Robson, Hartlepool. 



Mollusca. 



NOTES ON THE VARIATION OF SOME NORTH 

 AMERICAN MOLLUSCA. 



BY T. D. A. COCKERELL, F.Z.S., F.E.S., ETC. 



I have had the following notes in MS. for about three years, 

 together with others which are still held back. No systematic attempt 

 has yet been made in North America to describe and catalogue the 

 mutations of the land shells, owing to the general impression that this 

 is not worth doing ; but I suppose the matter will receive attention 

 later on, when there are no more new species to look for. Four of 

 the species treated of below are only aliens in North America. 



Agviolimax agrestis form varians Westerland. Mr. H. F. Wickham 

 sent me this from Portland, Oregon. It was pale grey, with heavy 

 black mottling coalescing on the mantle. 



A. agvestis form succineus Westerlund. Portland, Oregon. (H. F. 

 Wickham). The specimen is reddish-ochre above, with a faint 

 indication of grey marbling on the mantle. 



A. agvestis form sylvaticus Moq. I have received several specimens 

 both from Portland, Oregon (H. F. Wickham), and Houston, Texas 

 (W. W. Westgate). I also received one example from Dr. Cooper, 

 collected about 16 miles south of Hay wards, Cal. 



Zonites intemus form (Animalis) pallidtis. The animal cream-colour. 

 Binney, Man. Amer. Land Shells, p. 230. 



This cream-coloured (i.e. unpigmented) condition of the soft parts 

 is very interesting, the more so because it is usually not coincident 

 with the pigmentless condition of the shell. A freshwater species, 



