216 PROCEEDINGS OP THE ACADEMY OP [1884. 



affluents of the majestic Columbia River. The species ma^^, there- 

 fore, be regarded as strictly continental in its range, and until 

 very recently it has been distinctively American. It is a little 

 singular that the only other place in which it has been noticed is 

 in the neighborhood of Charkow, in Russia, where it was dis- 

 covered, a few months since, by Dr. L. Dybowski. 



The specimens of this species from Nova Scotia had been 

 collected by Mr. A. H. Mackay, B. A.,B. S., of Pictou Academy, 

 Pictou, N. S., from whom the speaker had recently received a 

 collection of sponges, phenomenal in its character, both as regards 

 the number of genera and species represented, and the excellent 

 judgment that had attached to most of them their proper names, 

 from apparently very insufficient data. The collection was the 

 result of few days' search within a limited district, " from lakes 

 in and near the water shed of Nova Scotia, near the borders 

 of the three counties of Pictou, Guysboro and Antigonish," at 

 elevations of from 100 to 700 feet above sea level. Of the genus 

 Spongilla^ it contains three species, S. lacustris^ S.fragilis, and 

 S. iglooiformis ; of the genus J^fej/ema, two species, M. fiuviatilis 

 and M. Everetti; of the genus Heteromei/enia, two, H. argy- 

 rosperma and H. Byderi, and of the genus TiibeUa, one species, T. 

 Pennayivanica — eight species, representing four genera. Besides 

 these there were small specimens of another species, evidently 

 new, but whose genus relations could not be determined on account 

 of the absence of statoblasts. 



In some respects the most important find in the collection is 

 Meyenia Everetti Mills ; this being only the second instance in 

 which the species has been discovered. The original locality was 

 Gilder Pond upon Mt. Everett, in Berkshire Co., Mass., at an 

 elevation of 1800 or 2000 feet above the sea. It was there col- 

 lected by Dr. F. Wolle and Mr. H. S. Kitchel of Bethlehem, Pa., 

 well known for their invaluable work among the desmids and 

 diatoms ; and examined simultaneously by Mr. H. Mills of Buf- 

 falo, N. Y., and the speaker. Its most striking peculiarity is the 

 presence, all through the dermal tissues, of very minute birot- 

 ulate spicules, the only instance in which these have been observed 

 as characteristic features of the dermal surface in any fresh-water 

 sponges ; unless the complicated forms found in Mtyenia plumosa 

 Carter, may be considered an exception. 



These birotulates in the present collection average one-third 

 longer than those before examined, and are in every way more 

 robust. The si)eaker was gratified in finding this confirmation of a 

 rule which he has long since observed to hold amongst the infinite 

 variations of size and form noticeable in collections of the same 

 species from various localities ; viz , that the spicules of all species 

 increase regularly in size and solidity as we descend from high 

 altitudes towards the sea-level, where is found the exti'eme limit 

 of the series. He does not attribute this gradation to a change 

 of climatic conditions, but more probably to a gradual and con- 



